[The effect and factors associated with outcome of extracorporeal membrane oxygenation in refractory cardiogenic shock patients].

Objective: To observe the clinical efficacy and factors associated with outcome of extracorporeal membrane oxygenation (ECMO) in refractory cardiogenic shock patients. Methods: Patients with refractory cardiogenic shock received ECMO treatment in our hospital from May 2013 to November 2015 were retrospectively analyzed. The clinical status before ECMO support, ECMO timing, complications and outcome were observed and analyzed.The hemodynamic data and the amount of vasoactive drugs at 2 hours before ECMO support and at 2, 6, 24 and 48 hours after ECMO support were collected and compared. Results: Ten refractory cardiogenic shock patients were included in this study (5 acute fulminant myocarditis patients, 4 acute myocardial infarction patients, 1 myocardial rupture patient (6 males, 4 females, age ranged 12 to 56 years). Before ECMO, the mean left ventricular ejection fraction (LVEF) was (31.4±10.2)%, the mean score of APACHE Ⅱ was 26.6±10.8. Eight patients developed cardiac arrests and the duration of CPR ranged from 10 to 300 minutes and three patients received IABP. CVP decreased, BP increased, HR decreased, ScVO2 increased, dose of dobutamine decreased at 2 hours after ECMO support. After ECMO support for 6 hours, lactate decreased, dose of norepinephrine decreased. After ECMO support for 24 and 48 hours, hemodynamics became stable and shock was significantly improved. Complication including infection of limb and catheterization site occurred in 3 patients, femoral arterial thrombosis occurred in 2 patients, critical limb ischemia occurred in 2 patients, hemorrhage at the catheterization site occurred in 2 patients. The duration of ECMO ranged from 2 to 220 hours. Nine patients could be weaned off ECMO support and 6 patients survived to hospital discharge. Two patients died due to too late ECMO support, the other two patients died due to severe complication of limb. Conclusions: ECMO can rapidly improve hemodynamic stability of patients with cardiogenic shock. Accurate assessing the timing of ECMO support and decreasing complication of limb play a critical role on improving outcome in refractory cardiogenic shock patients.

Broadband nonlinear optical response in multi-layer black phosphorus: an emerging infrared and mid-infrared optical material.

Black phosphorous (BP), the most thermodynamically stable allotrope of phosphorus, is a high-mobility layered semiconductor with direct band-gap determined by the number of layers from 0.3 eV (bulk) to 2.0 eV (single layer). Therefore, BP is considered as a natural candidate for broadband optical applications, particularly in the infrared (IR) and mid-IR part of the spectrum. The strong light-matter interaction, narrow direct band-gap, and wide range of tunable optical response make BP as a promising nonlinear optical material, particularly with great potentials for infrared and mid-infrared opto-electronics. Herein, we experimentally verified its broadband and enhanced saturable absorption of multi-layer BP (with a thickness of ~10 nm) by wide-band Z-scan measurement technique, and anticipated that multi-layer BPs could be developed as another new type of two-dimensional saturable absorber with operation bandwidth ranging from the visible (400 nm) towards mid-IR (at least 1930 nm). Our results might suggest that ultra-thin multi-layer BP films could be potentially developed as broadband ultra-fast photonics devices, such as passive Q-switcher, mode-locker, optical switcher etc.

Molybdenum disulfide (MoS2) as a broadband saturable absorber for ultra-fast photonics.

The nonlinear optical property of few-layered MoS2 nanoplatelets synthesized by the hydrothermal exfoliation method was investigated from the visible to the near-infrared band using lasers. Both open-aperture Z-scan and balanced-detector measurement techniques were used to demonstrate the broadband saturable absorption property of few-layered MoS2. To explore its potential applications in ultrafast photonics, we fabricated a passive mode locker for ytterbium-doped fibre laser by depositing few-layered MoS2 onto the end facet of optical fiber by means of an optical trapping approach. Our laser experiment shows that few-layer MoS2-based mode locker allows for the generation of stable mode-locked laser pulse, centered at 1054.3 nm, with a 3-dB spectral bandwidth of 2.7 nm and a pulse duration of 800 ps. Our finding suggests that few-layered MoS2 nanoplatelets can be useful nonlinear optical material for laser photonics devices, such as passive laser mode locker, Q-switcher, optical limiter, optical switcher and so on.

Regulation of proliferation and cytokine expression of bone marrow fibroblasts: role of c-myb.

The c-myb protooncogene plays a major role in regulating the process of in vitro and in vivo hematopoiesis via its activity as transcriptional regulator in hematopoietic progenitor cells. Since the bone marrow microenvironment appears to regulate in vivo hematopoiesis by maintaining the growth of multipotent progenitors via secretion of specific cytokines, we asked whether c-myb is also required for the proliferation of and/or cytokine production by stromal cells that generate fibroblast-like colonies (fibroblast colony-forming units [CFU-F]). Using the reverse transcriptase polymerase chain reaction technique, we detected low levels of c-myb mRNA transcripts in human normal bone marrow fibroblasts. Treatment of these cells with c-myb antisense oligodeoxynucleotides caused downregulation of c-myb expression, decreased in the number of marrow CFU-F colonies (approximately 54% inhibition) and in the cell number within residual colonies (approximately 80%), and downregulation of granulocyte/macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) mRNA expression. Transfection of T98G glioblastoma cells, in which expression of c-myb, GM-CSF, and SCF mRNAs is undetectable or barely detectable, with a plasmid containing a full-length c-myb cDNA under the control of the SV40 promoter induced the expression of biologically active SCF and GM-CSF in these cells. Regulation of GM-CSF expression by c-myb was due in part to transactivation of the GM-CSF promoter. These results indicate that, in addition to regulating hematopoietic cell proliferation, c-myb is also required for proliferation of and cytokines synthesis by bone marrow fibroblasts.

Noise-like pulse in a gain-guided soliton fiber laser.

We report on the operation of a passively mode-locked fiber ring laser made of purely positive dispersion fibers and mode-locked by using the nonlinear polarization rotation technique. It was experimentally found that apart from the gain-guided soliton operation the laser can also emit a kind of noise-like pulse. We show numerically that the noise-like pulse emission is caused by the peak power clamping effect of the laser cavity on the gain-guided soliton.

Loading of DNA-binding factors to an erythroid enhancer.

The HS-40 enhancer is the major cis-acting regulatory element responsible for the developmental stage- and erythroid lineage-specific expression of the human alpha-like globin genes, the embryonic zeta and the adult alpha2/alpha/1. A model has been proposed in which competitive factor binding at one of the HS-40 motifs, 3'-NA, modulates the capability of HS-40 to activate the embryonic zeta-globin promoter. Furthermore, this modulation was thought to be mediated through configurational changes of the HS-40 enhanceosome during development. In this study, we have further investigated the molecular basis of this model. First, human erythroid K562 cells stably integrated with various HS-40 mutants cis linked to a human alpha-globin promoter-growth hormone hybrid gene were analyzed by genomic footprinting and expression analysis. By the assay, we demonstrate that factors bound at different motifs of HS-40 indeed act in concert to build a fully functional enhanceosome. Thus, modification of factor binding at a single motif could drastically change the configuration and function of the HS-40 enhanceosome. Second, a specific 1-bp, GC-->TA mutation in the 3'-NA motif of HS-40, 3'-NA(II), has been shown previously to cause significant derepression of the embryonic zeta-globin promoter activity in erythroid cells. This derepression was hypothesized to be regulated through competitive binding of different nuclear factors, in particular AP1 and NF-E2, to the 3'-NA motif. By gel mobility shift and transient cotransfection assays, we now show that 3'-NA(II) mutation completely abolishes the binding of small MafK homodimer. Surprisingly, NF-E2 as well as AP1 can still bind to the 3'-NA(II) sequence. The association constants of both NF-E2 and AP1 are similar to their interactions with the wild-type 3'-NA motif. However, the 3'-NA(II) mutation causes an approximately twofold reduction of the binding affinity of NF-E2 factor to the 3'-NA motif. This reduction of affinity could be accounted for by a twofold-higher rate of dissociation of the NF-E2-3'-NA(II) complex. Finally, we show by chromatin immunoprecipitation experiments that only binding of NF-E2, not AP1, could be detected in vivo in K562 cells around the HS-40 region. These data exclude a role for AP1 in the developmental regulation of the human alpha-globin locus via the 3'-NA motif of HS-40 in embryonic/fetal erythroid cells. Furthermore, extrapolation of the in vitro binding studies suggests that factors other than NF-E2, such as the small Maf homodimers, are likely involved in the regulation of the HS-40 function in vivo.

Characterization of cell surface adenosine 3',5'-monophosphate-binding proteins in Y-1 mouse adrenal tumor cells.

Adrenal cortical cells are known to export cAMP and have binding proteins and cAMP-dependent protein kinase activity associated with their plasma membranes. Because these properties suggest a function for extracellular cAMP, we have undertaken a search for specific cell surface receptors for this cyclic nucleotide. Y-1 mouse adrenal tumor cells actively export cAMP by an energy-dependent process. Analysis of Scatchard plots of the equilibrium binding of [3H]cAMP to these cells indicate the existence of two classes of cAMP binders: one with high affinity (ka = 2.9 X 10(9) M-1) and another with low affinity (ka = 7.0 X 10(7) M-1). The cell surface localization of these binders was established by the sensitivity of both the [3H]cAMP-binding proteins and the [32P]8-N3-cAMP photoaffinity labeled proteins of intact cells to mild trypsin digestion and by the surface distribution of a BSA-O2-monosuccinyl cAMP-gold complex revealed by electron microscopy. Analysis of radioautograms of cell surface cAMP-binding proteins from confluent monolayer tumor cells, photoaffinity labeled with [32P]8-N3-cAMP and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two major 32P-labeled protein bands which were indistinguishable from the 49,000 and 55,000 mol wt regulatory subunits of the cytosolic protein kinase isoenzymes of this cell. These observations along with the demonstration of cell surface, cAMP-dependent protein kinase activity in the mouse adrenal tumor cell strongly suggest that these cAMP-binding proteins function as regulatory proteins for cell surface protein kinases.

Bound states of gain-guided solitons in a passively mode-locked fiber laser.

We report on the observation of bound states of gain-guided solitary pulses (GGSPs) in a dispersion-managed erbium-doped fiber laser. Despite the fact that the GGSP is a chirped pulse and there is strong pulse stretching and compression along the cavity in the laser, the bound GGSPs observed have a fixed pulse separation, which is invariant to the pump strength change. Numerical simulation confirmed the experimental observations and further showed that not only the pulse separation but also the relative phase difference between the bound GGSPs remained fixed along the cavity.

Gastroesophageal variceal bleeding caused by hepatoportal arteriovenous fistula.

Hepatoportal arteriovenous fistulas are usually traumatic in origin and may result in portal hypertension and serious complications. We report a 34-year-old female with a history of abdominal trauma, who developed symptoms of tarry stools and hematemesis 5 years later. Esophageal and gastric varices with bleeding were diagnosed by upper gastrointestinal endoscopy. Abdominal ultrasonography and computerized tomography favored noncirrhotic portal hypertension. An extrahepatic hepatoportal arteriovenous fistula was demonstrated by angiography. The patient underwent surgery to correct the condition. The liver had a smooth surface and both the common hepatic and gastroduodenal arteries were ligated during surgery. The postoperative course was uneventful. The varices later disappeared.

The effects of masseter muscle pain on biting performance.

The present study applied a standardized test food of known hardness to evaluate the biting performance of 20 female patients who had pain mainly in the masseter muscle during palpation. Another 20 women of a similar age group who were pain-free during examination served as controls. Electromyograms (EMG) of the masseter and sternocleidomastoid (SCM) muscles and the jaw position were recorded and measured when the subjects were biting through two types of test foods with known hardness (hard type, 20 kg hardness and extra-hard type, 60 kg hardness). Pressure-pain-threshold (PPT) values of both the patients and the normal subjects were obtained with an algometer. It was found that the PPT of the patients with pain was significantly lower and that the extra-hard food took more masseter muscle activity and more working side jaw movement in both the pain and the normal groups. During both hard and extra-hard food biting, a significantly longer duration of masseter muscle activity was found in pain patients while the total muscle activity was not significantly stronger. Strong correlation existed between SCM and masseter muscle activity during both hard and extra-hard food biting in the patient group, while such correlation was very weak in the normal group. In conclusion, painful masseter muscles required longer masseter and SCM muscle contraction time for breaking through a hard food of 20 kg and more, and co-activation of SCM and masseter muscles existed and was more evident when the food was harder or the pain was more severe.

Two major forms of DNA (cytosine-5) methyltransferase in human somatic tissues.

Thus far, only one major form of vertebrate DNA (cytosine-5) methyltransferase (CpG MTase, EC 2.1.1.37) has been identified, cloned, and extensively studied. This enzyme, dnmt1, has been hypothesized to be responsible for most of the maintenance as well as the de novo methylation activities occurring in the somatic cells of vertebrates. We now report the discovery of another abundant species of CpG MTase in various types of human cell lines and somatic tissues. Interestingly, the mRNA encoding this CpG MTase results from alternative splicing of the primary transcript from the Dnmt1 gene, which incorporates in-frame an additional 48 nt between exons 4 and 5. Furthermore, this 48-nt exon sequence is derived from the first, or the most upstream, copy of a set of seven different Alu repeats located in intron 4. The ratios of expression of this mRNA to the expression of the previously known, shorter Dnmt1 mRNA species, as estimated by semiquantitative reverse transcription-PCR analysis, range from two-thirds to three-sevenths. This alternative splicing scheme of the Dnmt1 transcript seems to be conserved in the higher primates. We suggest that the originally described and the recently discovered forms of CpG MTase be named dnmt1-a and dnmt1-b, respectively. The evolutionary and biological implications of this finding are discussed in relation to the cellular functions of the CpG residues and the CpG MTases.

ets-2 regulates cdc2 kinase activity in mammalian cells: coordinated expression of cdc2 and cyclin A.

ets-2 is a member of a family of transcription factors implicated in the regulation of gene expression during cell proliferation, cell differentiation, and development. We report that the ets-2 protein transactivates the promoter of the cdc2 gene which encodes a 34-kDa serine-threonine kinase required for mitotic initiation in mammalian cells. Transactivation occurs via specific interaction with multiple ets binding sites in the 5' flanking region of the gene. In BALB/c3T3 rodent fibroblasts constitutively expressing ets-2 and cultured in either 10 or 0.5% serum, cdc2 expression and its associated histone H1 kinase activity are increased, compared to control cells. Such increased activity correlates with elevated levels of cyclin A but not cyclin B1. Furthermore, ets-2-transfected, but not parental, BALB/c3T3 cells, grow under low serum conditions, albeit at a reduced rate. These data demonstrate that ets-2 plays a direct role in the regulation of cdc2 expression and raise the possibility that ets-2 participates in the coordinated regulation of cdc2 cyclin A expression which is essential for the modulation of cdc2-regulated processes.

Factors influencing the success rates of endoscopic nasobiliary drainage in treatment of obstructive jaundice.

BACKGROUND: Endoscopic nasobiliary drainage (ENBD) is a safe and effective modality which has been well documented for obstructive jaundice. However, factors predicting success rate of ENBD remain inconclusively. This study analyses those factors and discusses the outcome of patients with obstructive jaundice. METHODS: One hundred and sixteen patients (male 99, female 17; mean age 68.2 years) with obstructive jaundice received ENBD after endoscopic retrograde cholangiogram (ERC) by Olympus JF-lT20 endoscope and 7F Wilson-Cook nasobiliary catheter from Sep. 1990 to Oct. 1993. Bile output (QD), serum bilirubin (BIW), liver biochemistry (QW), bile culture (next day), blood culture (if BT > 38.5 degrees C) were checked until definite treatment or death. Adequate drainage was defined as a daily output of bile more than 200cc, a gradual drop in serum bilirubin and no signs of cholangitis. Factors such as causes of jaundice, obstruction level, serum bilirubin, albumin, juxtapapillary diverticulum (JPD), bacteremia, fever before ERCP and ascites were analyzed. RESULTS: The success rate was 86.2% (100/116) in ERC and 78% (78/100) in ENBD. Adequate biliary drainage was 82.1% (64/78), and serum bilirubin was reduced from 14.3 +/- 8.5 mg% to 7.5 +/- 5.6 mg% within one week. In patients with non-cancerous causes, higher success rate and adequate drainage rate were obtained compared with those with cancerous causes (94.3% vs. 69.2%, p < 0.01 and 88.6% vs. 50.8%, p < 0.01, respectively). In all patients, a higher success rate was achieved at the obstruction level at the common bile duct (CBD) compared with periampullary and hilar levels (90.7% vs 69.2%, p < 0.05 and 90.7% vs 28.6%, p < 0.001, respectively). In patients with cancer as a cause, higher success rate was achieved at CBD level than at hilar level (85% vs 28.6%, p < 0.05). Those patients with cancer and serum bilirubin above 15 mg/dl had a higher failure rate in ENBD. Success rate of ENBD was not related to the presence of JPD, bacteremia or fever before ERCP and serum albumin level. CONCLUSIONS: Factors decreasing the success rates of ENBD were underlying cancerous causes, obstruction level at hilum or periampullary region and serum bilirubin level more than 15 mg%.

c-myb transactivates cdc2 expression via Myb binding sites in the 5'-flanking region of the human cdc2 gene.

The c-myb protooncogene is preferentially expressed in hematopoietic cells and is required for cell cycle progression at the G1/S boundary. Because c-myb encodes a transcriptional activator that functions via DNA binding, it is likely that c-myb exerts its biological activity by regulating the transcription of genes required for DNA synthesis and cell cycle progression. One such gene, cdc2, encodes a 34-kDa serine-threonine kinase that appears to be required for G1/S transition in normal human T-lymphocytes. To determine whether c-myb is a transcriptional regulator of cdc2 expression, we subcloned a segment of a cdc2 human genomic clone containing extensive 5'-flanking sequences and part of the first exon. Sequence analysis revealed the presence of two closely spaced Myb binding sites that interact with bacterially synthesized Myb protein within a region extending from nucleotides -410 to -392 upstream of the transcription initiation site. A 465-base pair segment of 5'-flanking sequence containing these sites was linked to the CAT gene and had promoter activity in rodent fibroblasts. Cotransfection of this construct with a full-length human c-myb cDNA driven by the early simian virus 40 promoter resulted in a 6-8-fold enhancement of CAT activity that was abrogated by mutations in the Myb binding sites. These data suggest that c-myb participates in the regulation of cell cycle progression by activating the expression of the cdc2 gene.

Phosphatidylinositol-3 kinase activity is regulated by BCR/ABL and is required for the growth of Philadelphia chromosome-positive cells.

The BCR/ABL oncogenic tyrosine kinase is responsible for initiating and maintaining the leukemic phenotype of Philadelphia chromosome (Ph1)-positive cells. Phosphatidylinositol-3 (PI-3) kinase is known to interact with and be activated by receptor and nonreceptor tyrosine kinases. We investigated whether PI-3 kinase associates with and/or is regulated by BCR/ABL, whether this interaction is functionally significant for Ph1 cell proliferation, and, if so, whether inhibition of PI-3 kinase activity can be exploited to eliminate Ph1-positive cells from bone marrow. We show that the p85 alpha subunit of PI-3 kinase associates with BCR/ABL and that transient expression of BCR/ABL in fibroblasts and down-regulation of BCR/ABL expression using antisense oligodeoxynucleotides (ODNs) in Ph1 cells activates and inhibits, respectively, PI-3 kinase enzymatic activity. The use of specific ODNs or antisense constructs to downregulate p85 alpha expression showed a requirement for p85 alpha subunit in the proliferation of BCR/ABL-dependent cell lines and chronic myelogenous leukemia (CML) primary cells. Similarly, wortmannin, a specific inhibitor of the enzymatic activity of the p110 subunit of PI-3 kinase, inhibited growth of these cells. The growth of normal bone marrow and erythromyeloid, but not megakaryocyte, progenitors was inhibited by p85 alpha antisense [S]ODNs, but wortmannin, at the concentrations tested, did not affect normal hematopoiesis. The proliferation of two BCR/ABL- and growth factor-independent cell lines was not affected by downregulation of the expression of the p85 alpha subunit or inhibition of p110 enzymatic activity, confirming the specificity of the observed effects on Ph1 cells. Thus, PI-3 kinase is one of the downstream effectors of BCR/ABL tyrosine kinase in CML cells. Moreover, reverse transcriptase-polymerase chain reaction performed on single colonies to detect BCR-ABL transcripts showed that wortmannin was able to eliminate selectively CML-blast crisis cells from a mixture of normal bone marrow and Ph1 cells.

Derepression of human embryonic zeta-globin promoter by a locus-control region sequence.

A multiple protein-DNA complex formed at a human alpha-globin locus-specific regulatory element, HS-40, confers appropriate developmental expression pattern on human embryonic zeta-globin promoter activity in humans and transgenic mice. We show here that introduction of a 1-bp mutation in an NF-E2/AP1 sequence motif converts HS-40 into an erythroid-specific locus-control region. Cis-linkage with this locus-control region, in contrast to the wild-type HS-40, allows erythroid lineage-specific derepression of the silenced human zeta-globin promoter in fetal and adult transgenic mice. Furthermore, zeta-globin promoter activities in adult mice increase in proportion to the number of integrated DNA fragments even at 19 copies/genome. The mutant HS-40 in conjunction with human zeta-globin promoter thus can be used to direct position-independent and copy number-dependent expression of transgenes in adult erythroid cells. The data also supports a model in which competitive DNA binding of different members of the NF-E2/AP1 transcription factor family modulates the developmental stage specificity of an erythroid enhancer. Feasibility to reswitch on embryonic/fetal globin genes through the manipulation of nuclear factor binding at a single regulatory DNA motif is discussed.