Stark shift of a single barium ion and potential application to zero-point confinement in a rf trap.
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Journal Article↗
Biomedical subjects
X Zhao
Publications and source records attributed to X Zhao.
Calcium/calmodulin-dependent protein kinase types II and IV differentially regulate CREB-dependent gene expression.
Phosphorylation of CREB (cyclic AMP [cAMP]- response element [CRE]-binding protein) by cAMP-dependent protein kinase (PKA) leads to the activation of many promoters containing CREs. In neurons and other cell types, CREB phosphorylation and activation of CRE-containing promoters can occur in response to elevated intracellular Ca2+. In cultured cells that normally lack this Ca2+ responsiveness, we confer Ca(2+)-mediated activation of a CRE-containing promoter by introducing an expression vector for Ca2+/calmodulin-dependent protein kinase type IV (CaMKIV). Activation could also be mediated directly by a constitutively active form of CaMKIV which is Ca2+ independent. The CaMKIV-mediated gene induction requires the activity of CREB/ATF family members but is independent of PKA activity. In contrast, transient expression of either a constitutively active or wild-type Ca2+/calmodulin-dependent protein kinase type II (CaMKII) fails to mediate the transactivation of the same CRE-containing reporter gene. Examination of the subcellular distribution of transiently expressed CaMKIV and CaMKII reveals that only CaMKIV enters the nucleus. Our results demonstrate that CaMKIV, which is expressed in neuronal, reproductive, and lymphoid tissues, may act as a mediator of Ca(2+)-dependent gene induction.
Base Sequence↗
Induction of zebrafish (Brachydanio rerio) P450 in vivo and in cell culture.
1. Induction of zebrafish P450 by 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) was studied in liver tissue, primary liver cell culture and multipassage cell culture derived from zebrafish haploid and diploid embryos and liver. 2. TCDD induced two hepatic proteins (54 and 50 kDa) in vivo which were recognized by anti-trout P4501A1 IgG. The 54-kDa protein was induced by TCDD in primary and multipassage hepatocyte cultures and in haploid and diploid embryo-derived cells. The proteins in liver homogenates were not induced by aqueous exposure of zebrafish to beta-naphthoflavone (BNF). 3. Homogenates of zebrafish liver, cultured hepatocytes and embryo-derived cells also exhibited increased ethoxyresorufin O-deethylase (EROD) and 7-12-dimethyl-benz[a]anthracene (DMBA) hydroxylase activity following TCDD exposure.
Animals↗
[Evaluation of the clinical acute electrophysiological effects of propafenone using transesophageal atrial pacing].
The clinical acute electrophysiological effects of propafenone were evaluated using transesophageal atrial pacing (TEAP) in 65 patients with various arrhythmias. The mean age of the patients was 41 years. Incremental pacing and programmed ectopic stimulation were performed on each patient before and during drug administration. Propafenone was given as a bolus injection of 1.5mg.kg-1 body weight followed by drip infusion at a rate of 1 mg.min-1. S-R, P wave, P-R and QRS intervals were prolonged from 194.43 +/- 21.59, 97.49 +/- 10.92, 148.00 +/- 16.20 and 82.21 +/- 7.18ms 223.00 +/- 29.25, 100.22 +/- 10.60, 166.60 +/- 20.10 and 86.54 +/- 7.19ms, respectively (P < 0.005), A-V conduction system effective refractory period (AVCSERP) was prolonged from 316.35 +/- 82.97ms to 360.31 +/- 82.67ms (P < 0.0001) in the treated group. There was no change of atrial ERP and QTc interval (P > 0.05). Fast and slow pathway ERP was prolonged by 13% and 28% of the control value, respectively (P < 0.015), and accessory pathway ERP was prolonged from 278.89 +/- 27.13ms to 305.56 +/- 33.58ms (P < 0.001), in the treated group. Sinus cycle length, corrected sinus nodal recovery time and total sinus-atrial conductive time were significantly prolonged (P < 0.0001). The results can partially explain the antiarrhythmic effects and the side effects of propafenone. TEAP is dependable in evaluating the clinical electrophysiological effects of drugs.
Adolescent↗
[The effect of acupuncture on the function of macrophages in rats of immunodepression].
The immunodepression model was established by means of intraperitoneal injection of cyclophosphamide in rats. Their phagocytic percentage and phagocytic index of peritoneal macrophages (PM phi) as well as serum lysozyme (LSZ) decreased obviously; After 6 days of acupuncture at "Zusanli" points (ST 36), PM phi phagocytic percentage and phagocytic index increased significantly, Serum LSZ showed no significant change. These results indicate that acupuncture can increase the phagocytic function of M phi in rats of immunodepression, but Serum LSZ level does not synchronously increase with the phagocytic function of M phi.
Acupuncture Therapy↗
[Influence of endothelin-1 on ventricular fibrillation threshold in acute myocardial ischemic rats].
The influence of endothelin-1 on ventricular fibrillation threshold was studied in acute myocardial ischemic rats. Endothelin-1 (1.5-3.0 micrograms.kg-1 i.v.) given 5 min before ischemia reduced the ventricular fibrillation threshold in a dose- and time-dependent manner. Its effect lasted at least 60 min. A marked increase of spontaneous ventricular tachycardia and myocardial infarct size was seen and the arterial blood pressure was at a higher level (18.5-20.1/14.4-15.8 kPa) after 3.0 micrograms.kg-1. Diltiazem prevented partially from reduction of ventricular fibrillation threshold, eliminated completely the vasopressor response and limited the extension of myocardial necrosis induced by endothelin-1.
Animals↗
[An experimental observation on the influence of the different levels of estradiol on the nasal mucosa].
The histomorphological influences of ovariectomies and estradiol injections on the nasal mucosa were observed in adult female guinea pigs. In the mucosa of ovariectomized guinea pigs, degenerative changes including dissolving and desquamation of cilia and glandular hypotrophy were found. On the contrary, thickening layer of the epithelium, spongiosis and edema of the corium, hyperplasia of glands and increased density of cilia were observed in the mucosa of guinea pigs receiving estrogen. The results demonstrated that different levels of estrogen might have different effects on the nasal mucosa.
Animals↗
[Effect of sexual hormones on proliferation of laryngeal carcinoma cell line HEp-2 in vitro].
In this study, we observed the effect of FCS and DCC FCS on the proliferation of HEp-2 cell in vitro with dextran-coated charcoal technique, and explored the dose-dependence of HEp-2 cell to testosterone, 17 beta-estradiol and progesterone. The results showed that HEp-2 cell line is androgen-sensitive cell, and testosterone at concentration of 1 nmol/L and 10 nmol/L may stimulate the proliferation of HEp-2 cells, but 17 beta-estradiol and progesterone have no such effect. The results suggested that HEp-2 cell line is a proper model in vitro for the study of laryngeal carcinoma and sexual hormones. This study offered the evidences of the endocrine therapy for laryngeal carcinoma.
Cell Division↗
[The use of finite population sampling and lot quality assurance sampling in estimating "immunization coverage rate" in villages (towns)].
We have used Finite Population Sampling and Lot Quality Assurance Sampling (LQAS) in a field survey of "immunization coverage rate" for EPI in three villages (towns) in Lanxi Zhejiang Province. The results showed that there was no significant difference (P > 0.05) between the rates of two samplings and between the rate of sampling and population. These results indicated that both Finite population Sampling and LQAS are cheap and simple, and can represent the immunization coverage level of population.
Female↗
[The genetic mechanism of intersexuality in milk goats of Saanen breed of Xinong].
Intersexual goats of Saanen breed of Xinong at Northwestern Agricultural University were studied in anatomy, histology, cytogenetics and genetics. The different types of intersexuality were seen, ranging from psuedohermaphroditic female to male types, including testicular hypoplastic and sex reverse male. All of them were genetic female type (60, XX), the karyotype, normal, so the intersexual bodies caused by the gene, which located at autosomes, having masculinizing effect, and in homozygote made female turn to male incompletely. It was pointed that intersexuality and polledness were controlled by different genes, the half century standing problem on intersexual inheritance of goats has been solved. The normal: the intersexual = 3:1, but the intersexual came from genetic female, this is a very special segregative ratio.
Animals↗
Bone mass, rates of osteoporotic fractures, and prevention of fractures: are there differences between China and Western countries?
Fractures are one of the most common causes of disability in older women. The quantity and density of bone decreases with age. Most types of fractures increase as bone density declines. But most of the knowledge about causes and prevention of fractures comes from studies performed in Western countries. Asian women appear to have similar or slightly lower bone density that may be a result of their smaller size. They appear to have a lower risk of hip fracture than Whites, which may be a result of their shorter hip axis. The risks of other types of fractures in Chinese women is less well defined and reasons for differences in the rates of osteoporotic fractures between China and Western countries remain to be explored. A study is underway in Beijing to describe the risks and potential causes of fractures among older women in urban China. Randomized trials in Western countries have demonstrated that calcium and vitamin D, estrogen, calcitonin, or bisphosphonates can reduce the rate of fractures. increased intake of calcium and vitamin D may be the most effective approach to preventing fractures in China, but this should be tested in a randomized trial.
Asian People↗
Immunological and biochemical characterization of cytochromes P-450 in mullet (Mugil cephalus): comparison with rainbow trout P-450s.
Immunoblots (Western blot) of mullet liver microsomes revealed the presence of multiple forms of P-450 that appear to be structurally related to rainbow trout CYP1A1 and CYP2K1 and to P-450 LMC1 and LMC4, but not to LMC5. 3-Methylcholanthrene but not beta-naphthoflavone induced a major 58 kDa liver protein and a minor 56 kDa protein in mullet that both cross-reacted with anti-trout CYP1A1 IgG. The levels of immunodetectable P-450s and the activities of microsomal lauric acid hydroxylase, DMBA hydroxylase and progesterone 6 beta-hydroxylase were several times lower in mullet liver than in rainbow trout liver; however, progesterone 16 alpha-hydroxylase and progesterone 20 alpha-hydroxylase activities were 4-fold and 6-fold higher, respectively, in mullet than in trout liver.
Animals↗
Phorbol ester-induced apoptosis is accompanied by NGFI-A and c-fos activation in androgen-sensitive prostate cancer cells.
We have previously demonstrated the induction of the early response transcription factor NGFI-A in castration-induced regression of the rat ventral prostate. We have developed an in vitro model to investigate the role of kinase signal transduction and early transcriptional regulation in apoptosis of androgen-sensitive prostate cells. Cell death was induced in the androgen-sensitive human prostate line, LNCaP, by addition of the protein kinase activator, 12-tetradecanoylphorbol 13-acetate (TPA). TPA-induced death of LNCaP cells was asynchronous and exhibited morphological and ultrastructural features indicative of apoptosis. Specifically, cytoplasmic contraction, condensation of nuclear chromatin, and formation of membrane-bound "apoptotic bodies" were observed. Additionally, the characteristic endonuclease-generated DNA ladder, commonly associated with apoptosis, was observed in TPA-treated LNCaP cultures. TPA-induced LNCaP apoptosis was preceded by rapid yet transient induction of the early response transcription factors NGFI-A and c-fos. In dose-response experiments, NGFI-A and c-fos gene activation parallels the induction of death in LNCaP cells. TPA-induced expression of NGFI-A and c-fos and death of LNCaP cultures were blocked by pretreatment with staurosporine, a potent inhibitor of several protein kinases. Based on these studies, we suggest that activation of a TPA-inducible kinase(s) mediates apoptosis of androgen-sensitive prostate cells by means of an intracellular pathway that may involve the transient activation of the early response transcription factors NGFI-A and c-fos.
Alkaloids↗
Statistic method for determining the fusion-recombination of cellulase genome.
A hypothesis was proposed based on cellulase synergism and multiple variable statistics that the experimental value of N strains out of total fusants from the same cell fusion pool, Aspergillus niger x Trichoderma reesei, could be a sample for the definite fusion cross due to the independence and random of DNA recombination. It could be reduced if fusion recombination happened by analyzing the sample with the provided computer program selected 40 strains of about 2000 fusants of A. niger x T. reesei were analyzed under this procedure as an example and was showed that was effective method on guiding cellulase breeding.
Aspergillus niger↗
[Obliteration of empty sella for therapy of empty sella syndrome by transsphenoidal and transfrontal approach].
Seven cases of empty sella syndrome were reported, among them 2 cases were primary empty sella syndrome, 5 cases were secondary empty sella syndrome. 5 cases were operated with the obliteration by transsphenoidal approach, 2 cases were operated by transfrontal approach. 6 cases were cured, the symptoms in one case was not improved due to the primary hydrocephalus. This syndrome is associated with defect of sellar diaphragm, benign intracranial hypertension, long-term administration of Bromocriptine, surgery and radiotherapy of pituitary gland. Main clinical features are headache, damage of vision and visual fields, hypopituitarism. Obliteration of empty sella by transsphenoidal approach is a simple and effective method.
Adult↗
Glomerular volume expansion and mesangial cell mechanical strain: mediators of glomerular pressure injury.
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Animals↗
Quantitative determination of HLA-DR antigen expression on cell surfaces with monoclonal antibody by Dot-ELISA.
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Antibodies, Monoclonal↗
Mutations in the catalytic subunit of the cAMP-dependent protein kinase interfere with holoenzyme formation without disrupting inhibition by protein kinase inhibitor.
Three amino acids were identified in the catalytic (C) subunit of the cyclic AMP-dependent protein kinase that are involved in interaction with regulatory (R) subunit, but not with the specific protein kinase inhibitor, PKI. In a functional assay for gene induction, a C expression vector with serine or arginine substituted for Leu-198 and the double mutant C, His-87-->Gln/Trp-196-->Arg (Orellana, S. A., and McKnight, G. S. (1992) Proc. Natl. Acad. Sci, U.S.A. 89, 4726-4730), retained activity in the presence of an excess of RI or RII. In contrast, cotransfection of a full-length PKI expression vector completely inhibited the activity of both mutant and wild type C subunits. These data suggest that although the substrate/pseudosubstrate sites of R and PKI interact with C at the catalytic site, there is an additional domain on the C subunit that is involved in holoenzyme formation with R subunit and is distinct from sites specifying high affinity PKI binding.
Computer Simulation↗