Regulation Of Cyclic-amp Phosphodiesterase Of Rat Skeletal Myoblasts

The aim of the present investigation was to study the various regulatory mechanisms involved in the control of cAMP phosphodiesterases in rat skeletal myoblasts.;In rat skeletal myoblasts and adult muscle extracts, four forms of a high affinity cAMP phosphodiesterase are found in vitro. These are termed PDE I, PDE II, PDE III and PDE IV, and have approximately molecular weights of 1.5 x 10(\u276), 400,000, 120,000 and 60,000, respectively. Evidence is presented to show that there is only one primary form of phosphodiesterase in myoblasts, viz. PDE II, with the rest of the forms being derived from it.;In the presence of Bt(,2)cAMP or compounds which are able to augment in vivo concentrations of cAMP in the culture medium, the phosphodiesterase activity of skeletal myoblasts increases about 2-fold within 30 min of culture. Modification of PDE II can be demonstrated in cell-free extracts. Modification is entirely dependent on ATP and cAMP. Evidence is presented to show that during in vitro activation of phosphodiesterase, PDE II is phosphorylated.;When the myoblasts are exposed to Bt(,2)cAMP for 10-16 hours the activity of PDE III increases considerably. Spontaneous or Rous-Sarcoma virus-transformed myoblasts, however, show altered regulation of the two forms of PDE. In the presence of cAMP in the medium, unlike the nontransformed cells, the level of PDE III do not increase but the activity of PDE II rises. The altered moe of PDE regulation in transformed cells is dominant in hybrids between normal and transformed myoblasts

α-Adrenergic inhibition of proliferation in HepG2 cells stably transfected with the α1B-adrenergic receptor through a p42MAP kinase/p21Cip1/WAF1-dependent pathway

AbstractActivation of α1B adrenergic receptors (α1BAR) promotes DNA synthesis in primary cultures of hepatocytes, yet expression of α1BAR in hepatocytes rapidly declines during proliferative events. HepG2 human hepatoma cells, which do not express α1BAR, were stably transfected with a rat α1BAR cDNA (TFG2 cells), in order to study the effects of maintained α1BAR expression on hepatoma cell proliferation. TFG2 cells had a decreased rate of growth compared to mock transfected HepG2 cells as revealed by a decrease in [3H]thymidine incorporation into DNA. Stimulation of α1BAR with phenylephrine caused a further large reduction in TFG2 cell growth, whereas no effect on growth was observed in mock transfected cells. Reduced cell growth correlated with increased percentages of cells found in G0/G1 and G2/M phases of the cell cycle. In TFG2 cells, phenylephrine increased p42MAP kinase activity by 1.5- to 2.0-fold for up to 24 h and increased expression of the cyclin dependent kinase inhibitor protein p21Cip1/WAF1. Treatment of TFG2 cells with the specific MEK1 inhibitor PD98059, or infection with a −/− MEK1 recombinant adenovirus permitted phenylephrine to increase rather than decrease [3H]thymidine incorporation. In addition, inhibition of MAP kinase signaling by PD98059 or MEK1 −/− blunted the ability of phenylephrine to increase p21Cip1/WAF1 expression. In agreement with a role for increased p21Cip1/WAF1 expression in causing growth arrest, infection of TFG2 cells with a recombinant adenovirus to express antisense p21Cip1/WAF1 mRNA blocked the ability of phenylephrine to increase p21Cip1/WAF1 expression and to inhibit DNA synthesis. Antisense p21Cip1/WAF1 permitted phenylephrine to stimulate DNA synthesis in TFG2 cells, and abrogated growth arrest. These results suggest that transformed hepatocytes may turn off the expression of α1BARs in order to prevent the activation of a growth inhibitory pathway. Activation of this inhibitory pathway via α1BAR appears to be p42MAP kinase and p21Cip1/WAF1 dependent

Systemic Delivery of Oncolytic Adenoviruses Targeting Transforming Growth Factor-β Inhibits Established Bone Metastasis in a Prostate Cancer Mouse Model

Abstract We have examined whether Ad.sT?RFc and TAd.sT?RFc, two oncolytic viruses expressing soluble transforming growth factor-? receptor II fused with human Fc (sTGF?RIIFc), can be developed to treat bone metastasis of prostate cancer. Incubation of PC-3 and DU-145 prostate tumor cells with Ad.sT?RFc and TAd.sT?RFc produced sTGF?RIIFc and viral replication; sTGF?RIIFc caused inhibition of TGF-?-mediated SMAD2 and SMAD3 phosphorylation. Ad(E1-).sT?RFc, an E1? adenovirus, produced sTGF?RIIFc but failed to replicate in tumor cells. To examine the antitumor response of adenoviral vectors, PC-3-luc cells were injected into the left heart ventricle of nude mice. On day 9, mice were subjected to whole-body bioluminescence imaging (BLI). Mice bearing hind-limb tumors were administered viral vectors via the tail vein on days 10, 13, and 17 (2.5?1010 viral particles per injection per mouse, each injection in a 0.1-ml volume), and subjected to BLI and X-ray radiography weekly until day 53. Ad.sT?RFc, TAd.sT?RFc, and Ad(E1-).sT?RFc caused significant inhibition of tumor growth; however, Ad.sT?RFc was the most effective among all the vectors. Only Ad.sT?RFc and TAd.sT?RFc inhibited tumor-induced hypercalcemia. Histomorphometric and synchrotron micro-computed tomographic analysis of isolated bones indicated that Ad.sT?RFc induced significant reduction in tumor burden, osteoclast number, and trabecular and cortical bone destruction. These studies suggest that Ad.sT?RFc and TAd.sT?RFc can be developed as potential new therapies for prostate cancer bone metastasis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98454/1/hum%2E2012%2E040.pd

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Study of Bake-hardening behaviour of ultra-low carbon BH 220 steel at different strain rates

Automotive process adopts bake hardening technique during the paint baking cycle at elevated temperature for enhanced strength of steel by diffusion of carbon atoms to the dislocation along with drying of paint. The present study was intended to investigate the bake-hardening (BH) behaviour of ultra low carbon (0.0027wt % C)BH220 steel with different pre-strain values and to justify the work by dislocation density measurements. the specimen were subjected to tensile pre-strain of 2%, 4%, 6% and 8% at room temperature followed by bake hardening at predefined temperature of 170C for 20 minutes. Specimens with a particular pre-strain and prestrain with bake hardening were subjected to monotonic tensile load at different strain rates (0.001,0.1 and 100/s). Dislocation density was estimated by X-ray difraction technique. The results reveals that in case of quasi static strain rate tests, pre-straining increases the yeild strength compared to the as received steel in the range of 20-40%, where as in case of same prestrain and bake hardening combination it is in the range of 30-60%. Similar increase in ultimate tensile strength and bake bardening response was observed. Similar trend was also observed in case of high strain rate tests. This can be attributed, towards pinning of dislocation by bake hardening. In dislocation density study , increase in dislocation density was observed with increase in pre-strain level and as well as in strain rates

An Examination of the Tradeoff between Net Return, Risk, and Water Quality for Crop Rotations in South Central Kansas

This paper determined the optimal crop rotation in South Central Kansas. The model incorporated net return, risk, and water quality. In general, water quality improved as tillage was reduced within a rotation type and by adding an alfalfa rotation. The optimal crop rotation mixes included wheat, grain sorghum, soybeans, and alfalfa