Transcatheter closure of large fistula between left main coronary artery and right atrium using Amplatzer duct occluder.
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Balloon Occlusion↗
Biomedical subjects
X Q Shen
Publications and source records attributed to X Q Shen.
[Clinical evaluation of intermittent strophanthin K therapy for congestive heart failure combined coronary artery disease].
OBJECTIVE: To evaluate the effects and safety of intermittent strophanthin K therapy (ISKT) for congestive heart failure combined coronary artery disease with sinus rhythm. METHODS: Two hundred patients divided into Group A (98 cases with maintenance digoxin therapy) and Group B (102 cases with ISKT). They were studied for 3 months and some of them for longer period. RESULTS: Comparing the pretreatment data: 1. heart rate (HR, bpm), 2. left ventricular ejection fraction (LVEF), 3. blood pressure (Bp, mmHg, calculated values as mean Bp for statistics). In group A, item 1. and 2. were significantly improved (item 1. 88 +/- 12 and 68 +/- 12, P < 0.01; item 2. 0.32 +/- 0.12 and 0.40 +/- 0.12, P < 0.01; item 3. showed no significant difference (126 +/- 21/90 +/- 6 and 128 +/- 21/80 +/- 5, P > 0.05). In group B, item 1., 2. and 3. were significantly improved (item 1. 90 +/- 10 and 70 +/- 11, item 2. 0.32 +/- 0.10 and 0.45 +/- 0.10, item 3. 128 +/- +/- 20/91 +/- 7 and 110 +/- 10/76 +/- 10, the p valves are the same < 0.01). As compared with the posttreatment data of both group A and B, HR, P > 0.05, there was no significant difference, LVEF, P < 0.05, there was significant difference, Bp, P < 0.01, there was significant difference. It showed no significant difference in total occurrence rate of digitalis overload or toxication between two groups also. CONCLUSION: ISKT for congestive heart failure combined coronary artery disease with sinus rhythm is effective and safe, with better improvement of heart function and Bp level.
Adult↗
c-Jun potentiates the functional interaction between the amino and carboxyl termini of the androgen receptor.
The transactivation functions of the human androgen receptor (hAR) are regulated by several accessory factors that can be either positive or negative. One factor that has been previously shown to mediate hAR transactivation is the proto-oncoprotein c-Jun. The positive effect is a primary one, can be exerted by both endogenous and exogenous c-Jun, and requires multiple regions of c-Jun. However, the exact mechanism by which c-Jun exerts its enhancing function is unknown. In this study, we have used a mammalian two-hybrid system to ask if c-Jun influences the ligand-dependent amino- to carboxyl-terminal (N-to-C) interaction of hAR, which is thought to be responsible for the homodimerization of this receptor. Our results show that c-Jun enhances both hAR N-to-C terminal interaction and DNA binding in vitro. We have also tested a panel of c-Jun and c-Fos mutants for their activities on the N-to-C interaction, and the data demonstrate that the activities of these mutants parallel their activities on hAR transactivation. A mutation in the hAR activation function-2 (AF-2) abrogates N-to-C interaction, DNA binding, and transactivation, and these activities are not rescued by exogenous c-Jun. Interestingly, the p160 coactivator TIF2 can stimulate hAR N-to-C interaction, a finding consistent with the effect on hAR transactivation. These data strongly suggest that the hAR N-to-C interaction is the target of c-Jun action, and this activity requires a functional receptor AF-2.
Amino Acids↗
Regulation of transcription by AMP-activated protein kinase: phosphorylation of p300 blocks its interaction with nuclear receptors.
AMP-activated protein kinase (AMP-kinase) modulates many metabolic processes in response to fluctuations in cellular energy status. Although most of its known targets are metabolic enzymes, it has been proposed that AMP-kinase might also regulate gene expression. Here we demonstrate that the transcriptional coactivator p300 is a substrate of AMP-kinase. Phosphorylation of p300 at serine 89 by AMP-kinase dramatically reduced its interaction, in vitro and in vivo, with the nuclear receptors peroxisome proliferator-activated receptor gamma, thyroid receptor, retinoic acid receptor, and retinoid X receptor, but did not affect its interaction with the non-nuclear receptor transcription factors E1a, p53, or GATA4. These findings indicate that the AMP-kinase signaling pathway selectively modulates a subset of p300 activities and represent the first example of a transcriptional component regulated by AMP-kinase. Our results suggest a direct link between cellular energy metabolism and gene expression.
AMP-Activated Protein Kinases↗
[Effects of percutaneous transluminal coronary angioplasty and stenting on QT dispersion in patients with coronary heart disease].
OBJECTIVE: The aim of this study was to approach the effects of percutaneous transluminal coronary angioplasty (PTCA) and stenting on QT dispersion (QTd) in patients with coronary heart disease. METHODS: PTCA and stenting were performed successfully on 42 patients with coronary heart disease. QTd and corrected QTd (QTcd) were obtained with a standard 12-lead ECG before and after PTCA + Stent. RESULTS: QTd and QTcd after PTCA + Stent were reduced significantly compared to those before PTCA + Stent (P < 0.01). There were no significant difference in QTd and QTcd before PTCA + Stent between single vessel lesion and multi-vessel lesion, but after PTCA + Stent, QTd and QTcd in single vessel lesion were decreased significantly compared to those in multi-vessel lesion. The ventricular arrhythmia in 9 patients was over after PTCA + Stent. CONCLUSIONS: QTd and QTcd were decreased significantly after PTCA + Stent because of the improvement of myocardial ischemia and heterogeneous repolarization in patients with coronary heart disease. The degree in decreasing QTd and QTcd was associated with compensatory circulation in coronary artery.
Adolescent↗
c-Jun targets amino terminus of androgen receptor in regulating androgen-responsive transcription.
The human androgen receptor (hAR) is a member of the nuclear receptor superfamily and functions as a ligand-inducible transcription factor. We have previously proposed that c-Jun mediates the transcriptional activity of this receptor. The modular nature of hAR was used in this study to generate several fusions with the heterologous DNA-binding domain of the yeast transcription factor GAL4 in an attempt to identify the c-Jun-responsive domains within the receptor. Our results suggest that the target of c-Jun action is the amino terminus (AB region) of the receptor and that hAR amino acids 502-521 are critical for the c-Jun response. Additionally, amino acids 503-555 were shown to harbor an autonomous transactivation that is stimulated by c-Jun. Furthermore, we demonstrated that transcription intermediary factor-2 (TIF-2), a coactivator that acts on the activation function-2, stimulates the full-length hAR. These results suggest that c-Jun and TIF-2 can work together as coactivators on the hAR by targeting distinct portions of the receptor.
Androgens↗
[A study on thermal decomposition mechanism and quality analysis of pearl powder].
OBJECTIVE: To establish a rapid and convenient method for distinguishing genuine from sham of pearl powder as well as appraising its quality preliminarily. METHOD: Thermogravimetry and differential thermogravimetry. RESULT: The TG and DTG curves can be divided into two characteristic regions. The first step ranges from 250 to 380 degrees C with a weight loss of about 3%, resulting from the denaturalization and decomposition of organic matter in the powder; and the second step from 600 to 780 degrees C with a weight loss of about 40% resulting from the decomposition of calcium carbonate in the powder. CONCLUSION: According to the two characteristic regions on TG and DTG curves along with corresponding parameters, pearl powder can be appropriately authenticated. Being related directly to the contents of organic matter in pearl powder, the first step is an important criterion for quality appraisal.
Animals↗
Ligand-free RAR can interact with the RNA polymerase II subunit hsRPB7 and repress transcription.
Upon binding retinoic acid (RA), the retinoic acid receptors (RARs) are able to positively and negatively regulate transcription. It has been shown that the DNA-binding domain and carboxy terminus of RARs are necessary for the ligand-dependent ability of the receptor to repress AP-1 transcriptional activity. A fusion of these two regions, shown to constitutively inhibit AP-1 activity, was used in a yeast two-hybrid screen to identify a novel hRARalpha-interacting protein. This protein, hsRPB7, a subunit of RNA polymerase II, interacts with hRARalpha in the absence of RA and addition of RA disrupts the interaction. Truncation analysis indicates that hsRPB7 specifically interacts with the hRARalpha DNA-binding domain. This interaction appears to compromise transcription, since overexpressed hRARalpha, in the absence of RA, is able to repress the activity of several RNA polymerase II-dependent activators, including AP-1 and the glucocorticoid receptor. This repression is relieved by transfected hsRPB7, strongly suggesting that ligand-free hRARalpha can block AP-1 activity by sequestering hsRPB7. The repression is dependent on the integrity of the hRARalpha DBD, since a mutation within the DBD blocks both the hRARalpha-hsRPB7 interaction and ligand-free hRARalpha repression of AP-1. These results provide evidence that non-liganded hRARalpha can regulate transcription by directly interacting with RNA polymerase II, and thus suggest a novel pathway by which hRARalpha can cross-talk with AP-1 and perhaps other families of transcriptional activators.
Animals↗
Ligand-activated retinoic acid receptor inhibits AP-1 transactivation by disrupting c-Jun/c-Fos dimerization.
In the presence of retinoic acid (RA), the retinoid receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR), are able to up-regulate transcription directly by binding to RA-responsive elements on the promoters of responsive genes. Liganded RARs and RXRs are also capable of down-regulating transcription, but, by contrast, this is an indirect effect, mediated by the interaction of these nuclear receptors not with DNA but the transcription factor activating protein-1 (AP-1). AP-1 is a dimeric complex of the protooncoproteins c-Jun and c-Fos and directly regulates transcription of genes important for cellular growth. Previous in vitro results have suggested that RARs can block AP-1 DNA binding. Using a mammalian two-hybrid system, we report here that human RARalpha (hRARalpha) can disrupt in a RA-dependent manner the homo- and heterodimerization properties of c-Jun and c-Fos. This inhibition of dimerization is cell specific, occurring only in those cells that exhibit RA-induced repression of AP-1 transcriptional activity. Furthermore, this mechanism appears to be specific for the RARs, since another potent inhibitor of AP-1 activity, the glucocorticoid receptor, does not affect AP-1 dimerization. Our data argue for a novel mechanism by which RARs can repress AP-1 DNA binding, in which liganded RARs are able to interfere with c-Jun/c-Jun homodimerization and c-Jun/c-Fos heterodimerization and, in this way, may prevent the formation of AP-1 complexes capable of DNA binding.
Animals↗
c-Fos dimerization with c-Jun represses c-Jun enhancement of androgen receptor transactivation.
The transcriptional activity of the human androgen receptor (hAR), like other nuclear receptors, is dependent on accessory factors. One such factor is c-Jun, which has been shown to have a selective function of mediating androgen receptor-dependent transactivation. This c-Jun activity is inhibited by c-Fos, another protooncoprotein that can dimerize with c-Jun to form the transcription factor AP-1. Here we show that c-jun mediates hAR-induced transactivation from the promoter of the androgen-regulated gene, human kallikrein-2 (hKLK2), and c-Fos blocks this activity. Using c-Fos truncation mutants and measuring hKLK2-dependent transcription, we have determined that the bZIP region of c-Fos is required and sufficient for inhibiting c-Jun enhancement of hAR transactivation. Further truncation analysis of the bZIP shows that the c-Fos dimerization function, mediated through the leucine zipper, is essential for the negative activity, whereas DNA binding, mediated through the basic region, is dispensable. These results suggest that heterodimerization by c-Fos with c-Jun blocks c-Jun's ability to enhance hAR-induced transactivation.
Animals↗
c-Jun can mediate androgen receptor-induced transactivation.
The proto-oncoprotein c-Jun forms as a heterodimer with c-Fos, the transcription factor AP-1. AP-1 regulates transcription through transactivation, a process requiring DNA binding. Here we report an indirect mechanism by which c-Jun can regulate transcription via the androgen receptor. In this process, c-Jun is able to support androgen receptor-mediated transactivation in the absence of an interaction with c-Fos or any apparent DNA binding. This positive effect of c-Jun was dose-dependent. Both exogenously added and endogenously induced c-Jun are able to act on the androgen receptor. Transactivation by the androgen receptor can undergo self-squelching, and this was relieved by transfected c-Jun. Using a time-course experiment, we provide evidence that the c-Jun effect is primary. c-Fos is able to block human androgen receptor activity in both the absence and presence of transfected c-Jun. Using a modified form of the yeast two-hybrid system, we show in Cos cells that c-Jun can interact with the DNA binding domain/hinge region (CD regions) of the androgen receptor. Therefore, we propose that c-Jun functions as a mediator for androgen receptor-induced transactivation.
Animals↗
Dimerization interfaces formed between the DNA binding domains determine the cooperative binding of RXR/RAR and RXR/TR heterodimers to DR5 and DR4 elements.
We have previously reported that the binding site repertoires of heterodimers formed between retinoid X receptor (RXR) and either retinoic acid receptor (RAR) or thyroid hormone receptor (TR) bound to response elements consisting of directly repeated PuG(G/T)TCA motifs spaced by 1-5 bp [direct repeat (DR) elements 1-5] are highly similar to those of their corresponding DNA binding domains (DBDs). We have now mapped the dimerization surfaces located in the DBDs of RXR, RAR and TR, which are responsible for cooperative interaction on DR4 (RXR and TR) and DR5 (RXR and RAR). The D-box of the C-terminal CII finger of RXR provides one of the surfaces which is specifically required for the formation of the heterodimerization interfaces on both DR4 and DR5. Heterodimerization with the RXR DBD on DR5 specifically requires the tip of the RAR CI finger as the complementary surface, while a 7 amino acid sequence encompassing the 'prefinger region', but not the TR CI finger, is specifically required for efficient dimerization of TR and RXR DBDs on DR4. Importantly, DBD swapping experiments demonstrate not only that the binding site repertoires of the full-length receptors are dictated by those of their DBDs, but also that the formation of distinct dimerization interfaces between the DBDs are the critical determinants for cooperative DNA binding of these receptors to specific DRs.
Amino Acid Sequence↗
The dimerization interfaces formed between the DNA binding domains of RXR, RAR and TR determine the binding specificity and polarity of the full-length receptors to direct repeats.
Heterodimers of retinoid X receptor (RXR) and retinoic acid receptor (RAR) bind preferentially to directly repeated elements with spacing of two (DR2) or five (DR5) base pairs, due to the specific heterocooperative interaction of their DNA binding domains (DBDs) on these elements. We have demonstrated in the accompanying paper that the heterodimeric DBD interface that is responsible for the cooperative binding to DR5 elements, specifically involves the D-box of the RXR CII finger and the tip of the RAR CI finger. We show here that a second type of dimerization interface, which specifically implicates the RAR T-box and the RXR CII finger to the exclusion of the D-box, determines the selective binding to DR2 elements. Interestingly, the same type of dimerization interface (RXR T-box and CII finger) is responsible for the cooperative binding of homodimers of the RXR DBD to DR1 elements. Based on the three-dimensional structure of the glucocorticoid receptor DBD, modeling of RXR/RAR, RXR/TR and RXR/RXR DBD cooperative interactions predicts that in all cases the DBD contributing the CII finger, i.e. that of RXR, has to be positioned 5' to its cooperatively bound partner. This binding polarity of the DBDs is conferred upon the full-length receptors, since crosslinking experiments indicate that RXR is always 5' to RAR in complexes between either DR5 or DR2 and RXR/RAR heterodimers. The possible significance of these observations for transactivation by retinoic acid receptors is discussed.
Base Sequence↗
[Comparative study of single-point method and multipoint method in the measurement of estrogen receptor and progesterone receptor in breast cancer].
A comparative study of estrogen receptor (ER) and progesterone receptor (PgR) by single-point method and multi-point method in dextran coated charcoal assay (DCC) was carried out in 50 and 47 cases of breast cancer, respectively. Taking 10 fmol/mg protein as the positive value, the conformation rate of both methods in ER measurement was 96.0% (48/50) with r = 0.978 by linear regression analysis (P less than 0.001). In PgR measurement, the conformation rate of both methods was 95.7% with r = 0.988 (P less than 0.001). Statistically, the difference between single-point method and multi-point method in the ER and PgR measurements was not significant (P greater than 0.5) both in rank-sum test and in paired t-test. The authors suggest that ER and PgR of breast cancer samples be measured with single-point method for its simplicity and less tumor tissue required.
Breast Neoplasms↗