Activities of adenovirus virus-associated RNAs: purification and characterization of RNA binding proteins

Most human adenoviruses encode two virus-associated (VA) RNAs, VA RNAI and VA RNAII, that accumulate to high levels in the cytoplasm of infected cells. The function of VA RNAI in blocking the activation of the cellular kinase PKR is well known, but the role of VA RNAII is obscure. Herein we characterize and purify several human proteins that interact preferentially with VA RNAII in Northwestern blot assays. Two of these proteins were identified as RNA helicase A and NF90, a component of the heterodimeric nuclear factor of activated T cells (NFAT). They copurified with the smaller NFAT subunit, NF45, which did not bind VA RNAII, and with an unidentified protein, p97, which did bind VA RNAII. Both RNA helicase A and NF90 contain two copies of a double-stranded (ds) RNA binding motif and bind strongly to dsRNA. NF90 interacts with RNAs in the following order of affinity: dsRNA > VA RNAII > VA RNAI > single-stranded RNA. Furthermore, VA RNAII is more effective than VA RNAI as an inhibitor of RNA helicase activity. These data identify RNA helicase A and NF90 as cellular proteins with an affinity for dsRNA and other structured RNA molecules and suggest that their functions are subject to regulation by RNA ligands including VA RNAII.     

Acute effects of chundosunbup qi-training on blood concentrations of TSH, calcitonin, PTH and thyroid hormones in elderly subjects

The present study investigated how the systemic treatment of a programmed exercise, ChunDoSunBup (CDSB) Qi-training, affects the secretion of thyroid and parathyroid hormones in elderly subjects (10 male and 5 female). Plasma concentrations of thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), parathyroid hormone (PTH), ionized calcium, and calcitonin were determined. CDSB Qi-training induces a slight increase in TSH. Both T4 and T3 were increased at the mid-time of CDSB Qi-training (p < 0.05). There were significant correlations only between T3 and T4 at mid-training. This shows that increase in the plasma level of T3 was associated with the secretion of T4. The plasma concentrations of calcitonin and PTH were increased at mid-time and post-time of CDSB Qi-training. But ionized calcium was decreased slightly by CDSB Qi-training. These results suggest that Qi-training modulates the secretion of thyroid hormones, calcium metabolism, and parathyroid hormones in the elderly. However, whether the long-term practice of CDSB Qi-training might change bone metabolism and have longitudinal effects on the thyroid hormone of the elderly need further investigation.     

Pharmacological characterization of a simple behavioral response mediated selectively by central adenosine A1 receptors, using in vivo and in vitro techniques

Mouse embryonic carcinoma P19 cell aggregates treated with retinoic acid (RA) sequentially differentiate into neurons and astrocytes, whereas attached cells develop a mesodermal phenotype. The expression of calcitonin (CT) and PTH/PTH-related protein (PTHrP) receptors was investigated in embryonic cells, and during neural and mesodermal differentiation. In embryonic P19 cells, specific binding of [125I]salmon (s) CT(1-32) ([125I]sCT(1-32)) was 56 fmol/mg protein, and of [125I]chicken (ch) [Tyr36]PTHrP(1-36) amide ([125I]chPTHrP(1-36)) < 0.5 fmol/mg protein. Correspondingly, cAMP was maximally stimulated 47-fold by sCT(1-32) (EC50 0.05 nM) and 3-fold by chPTHrP(1-36) (EC50 1.3 nM). Receptor autoradiography revealed specific binding of [125I]sCT(1-32) to the undifferentiated P19 cells, but not to RA induced neurons and astrocytes. At the same time, [125I]sCT(1-32) binding and cAMP accumulation by sCT were gradually decreased. But, specific binding of [125I]chPTHrP(1-36) was raised at least 6-fold compared with embryonic cells to 3 fmol/mg protein, in parallel with a 10-fold higher maximal cAMP accumulation. A similar, but delayed suppression of CT and stimulation of PTH/PTHrP receptor expression was observed during mesodermal cell differentiation. The results indicate that CT receptors are associated with undifferentiated P19 cells, whereas PTH/PTHrP receptors are expressed in RA induced neural and mesodermal cells.     

Plasma L-arginine concentration, oxygenation index, and systemic blood pressure in premature infants

OBJECTIVE: To determine the relationships between plasma L-arginine concentrations and the severity of respiratory distress syndrome (RDS) or systemic blood pressure in premature infants. DESIGN: Prospective, observational study. SETTING: Neonatal intensive care, tertiary referral hospital. SUBJECTS: Fifty-three premature infants. INTERVENTIONS: We measured arginine and nutritional intake, plasma arginine concentration, total amino acid concentrations, and blood pressure on days 3, 7, 14, and 21 of life. In 33 infants who received assisted ventilation, oxygenation index could be calculated to reflect the severity of RDS. The relationships between plasma arginine and oxygenation index or blood pressure were analyzed using multiple linear regression. MEASUREMENTS AND MAIN RESULTS: On day 3, plasma arginine concentrations were decreased compared with normal published values. Arginine concentrations increased with the day of life of measurement (p < .001) and with arginine intake (p < .001). After adjusting for arginine intake and day of life, an inverse relationship was found between oxygenation index and plasma arginine concentrations: (p = .025). No similar relationship was found between oxygenation index and the concentration of total amino acids. A weak positive relationship was found between plasma arginine concentration and systemic blood pressure. CONCLUSIONS: Increments in the oxygenation index, reflective of an increased severity of RDS, are associated with a decrease in plasma arginine concentration. This finding may reflect arginine consumption by the nitric oxide synthase pathway in the lungs of premature infants with RDS, or may be explained by increased arginine catabolism. The lack of a similar relationship between total plasma amino acids and oxygenation index supports the first interpretation.     

Growth behavior of fibroblasts on microgrooved polystyrene

We investigated the contact guidance phenomenon of rat dermal fibroblasts (RDF) on microgrooved polystyrene substrates. Grooves were 1 microm deep, and between 1 and 10 microm wide. Light microscopy and digital image analysis (DIA) showed that RDF were oriented on all microgrooved substrates. Scanning electron microscopy showed that RDF cultured on 1 or 2 microm wide grooves were positioned on top of the ridges. On the wider 5 and 10 microm grooves, the cells were able to descend into the grooves. In confocal laser scanning microscopy, focal adhesions were lying in the same direction as the actin filament where they attached to. DIA confirmed an orientational behavior of focal adhesions and actin filaments on microgrooves. There were no differences in the measured orientation between the different grooves. Besides, no obvious preference was found for focal adhesions to lie along edges of the surface ridges. Transmission electron microscopy showed that focal adhesions were able to bend along the edges of ridges. On the basis of our observations, we suggest that the breakdown and formation of fibrous cellular components, especially in the filopodium, is influenced by the microgrooves. The microgrooves create a pattern of mechanical stress, which influences cell spreading and cause the cell to be aligned with surface microgrooves.     

Proton magnetic resonance spectroscopy of linear nevus sebaceus syndrome

OBJECTIVE: The potential effect of ethnicity on the serum lipid profile and lipoprotein(a) [Lp(a)] was studied in a population with chronic spinal cord injury (SCI). STUDY DESIGN: The distribution and correlates of high density lipoprotein (HDL) cholesterol and Lp(a) were studied in a population of 600 subjects with chronic SCI. RESULTS: Mean +/- SEM serum HDL cholesterol was significantly higher in the African American group than in the white and Latino groups (47 +/- 1 vs 40 +/- 1 and 38 +/- 1 mg/dL, p < .0001, respectively). The African American group had a lower serum total to HDL cholesterol ratio than white and Latino groups (4.46 +/- .153 vs 5.18 +/- .168 and 5.40 +/- .140 mg/dL, p < .01, respectively). Mean serum Lp(a) levels were significantly higher in the African American group than in Latino or white groups (29 +/- 2 vs 18 +/- 1 and 15 +/- 1 mg/dL, p < .0001, respectively). Age, duration of SCI, and level and completeness of lesion had no significant effect on serum Lp(a) level. CONCLUSIONS: In a population with chronic SCI, those in the African American group had the highest serum HDL cholesterol concentrations, the lowest serum total to HDL cholesterol ratios, and elevated levels of serum Lp(a) compared with the Latino and white groups. In a population of individuals with chronic SCI, ethnicity was shown to have a major effect on serum lipids and may be used to assist in the determination of cardiovascular risk.     

Study of the non-steady state electrogenic transport of sodium ions by Na+,K(+)-ATPase by the capacitance measurement method

The goal of work was to investigate the electrogenic transport of Na ions by Na+,K(+)-ATPase in membrane fragments absorbed on a planar bilayer lipid membrane. The photorelease of ATP from an inactive precursor, caged ATP, induced a transient current and changes in the net system capacitance measured during the application of an alternating voltage. The increments of capacitance (delta c) decreased with the increase in the frequency of the applied voltage. The characteristic frequency F0 of the steepest slope of the curve significantly decreased in solutions with high ionic strength (either NaCl or choline chloride), in which Na+ transport is decelerated. The value of delta c correlated with the total charge delta q transported across the membrane. The capacitance increments decreased when the Na+ concentration in solution decreased. At a concentration below 2 mM the increment became negative. The increase in membrane capacitance can be attributed to the charge relaxation process inside the protein, as discovered in the cells by other methods. The characteristic frequency F0 depends on the time constants of charge redistribution. The nonlinear dependences of delta c on delta q were explained by a voltage bias across the membrane fragments resulting from pumping. The potentials corresponding to the maximum capacitance change were similar to the midpoint potentials of the equilibrium charge distribution and depended on the Na+ concentrations in solution. The model enabled also the determination of the total capacitance of the active region of a lipid membrane with the adsorbed protein containing membrane fragments.