Time-stretched photonic Doppler velocimetry.

Inertial confinement fusion facilities generate implosions at speeds greater than 100 km/s, and measuring the material velocities is important and challenging. We have developed a new velocimetry technique that uses time-stretched spectral interferometry to increase the measurable velocity range normally limited by the detector bandwidth. In this approach, the signal is encoded on a chirped laser pulse that is stretched in time to reduce the beat frequency before detection. We demonstrate the technique on an imploding liner experiment at the Sandia National Laboratories' Z machine, where beat frequencies in excess of 50 GHz were measured with 20 GHz bandwidth detection.

Cancer cells express aberrant DNMT3B transcripts encoding truncated proteins.

Cancer cells display an altered distribution of DNA methylation relative to normal cells. Certain tumor suppressor gene promoters are hypermethylated and transcriptionally inactivated, whereas repetitive DNA is hypomethylated and transcriptionally active. Little is understood about how the abnormal DNA methylation patterns of cancer cells are established and maintained. Here, we identify over 20 DNMT3B transcripts from many cancer cell lines and primary acute leukemia cells that contain aberrant splicing at the 5' end of the gene, encoding truncated proteins lacking the C-terminal catalytic domain. Many of these aberrant transcripts retain intron sequences. Although the aberrant transcripts represent a minority of the DNMT3B transcripts present, Western blot analysis demonstrates truncated DNMT3B isoforms in the nuclear protein extracts of cancer cells. To test if expression of a truncated DNMT3B protein could alter the DNA methylation patterns within cells, we expressed DNMT3B7, the most frequently expressed aberrant transcript, in 293 cells. DNMT3B7-expressing 293 cells have altered gene expression as identified by microarray analysis. Some of these changes in gene expression correlate with altered DNA methylation of corresponding CpG islands. These results suggest that truncated DNMT3B proteins could play a role in the abnormal distribution of DNA methylation found in cancer cells.

SU proteins from virulent and avirulent EIAV demonstrate distinct biological properties.

Biologic activity of equine infectious anemia virus (EIAV) surface (SU) glycoprotein was assayed in a mouse model. Recombinant SU from virulent EIAV17 (SU17), administered intraperitoneally to mouse pups, induced dose-dependent diarrheal responses similar to those reported for SIV SU (Virology 277 (2000) 250). SU17 caused fluid accumulation without histological lesions in mouse intestinal loops, induced chloride secretory currents in Ussing chambers and increased inositol 1,4,5 triphosphate (IP3) levels in HT29 cells. An SU17 peptide, SU17(299-330), provoked a dose-dependent diarrheal response akin to enterotoxic peptides from SIV. In contrast, SU from an avirulent EIAV strain failed to induce a dose response in mouse pups and produced lower levels of activity than SU17 in Ussing chambers and IP3 assays. These results demonstrate that a mouse pup model is useful to monitor EIAV SU biologic activity, showing clear differences between the activities of SU derived from virulent and avirulent viruses, and may provide a useful screen of EIAV virulence.

Differential effects of virulent and avirulent equine infectious anemia virus on macrophage cytokine expression.

Equine infectious anemia virus (EIAV) causes rapid development of acute disease followed by recurring episodes of fever, thrombocytopenia, and viremia. Most infected equid eventually bring the virus under immunological control. We recently reported the development of an equine-specific ribonuclease protection assay (RPA) to quantitate mRNA levels of 10 cytokines. Using this newly developed RPA, we now show significant differences in cytokine induction in equine monocyte-derived macrophages (EMDM) exposed to virulent and avirulent EIAV. Virulent EIAV17 induced significant increases in interleukin (IL)-1alpha, IL-1beta, IL-6, IL-10, and tumor necrosis factor (TNF)-alpha by 0.5-1 h postinfection (hpi). In contrast, the avirulent virus failed to induce any of the tested cytokines above that of control levels. These data show a direct correlation between cytokine dysregulation and EIAV pathogenesis.

Simultaneous quantitation of equine cytokine mRNAs using a multi-probe ribonuclease protection assay.

A rapid multi-probe ribonuclease protection assay (RPA) was developed to quantitate equine-specific cytokine mRNA levels in activated equine monocyte-derived macrophages (EMDM) and equine peripheral blood mononuclear cells (EPBMC). Eleven template plasmids specific to 10 equine cytokine genes and the beta-actin gene were generated from which radiolabeled anti-sense RNA probes were produced. The multi-probe RPA simultaneously quantitated mRNA levels of equine IL-1alpha, IL-1beta, IL-6, IL-8, IL-10, IL-12 p35, IL-12 p40, IFN-gamma, TGF-1beta and TNF-alpha in EPBMC and EMDM with coefficients of variation as low as 0.03-0.08 (3-8%) when normalized to beta-actin expression. This sensitive and rapid assay provides a valuable tool for studies of equine immune responses.

Economic evaluation of lamivudine compared with interferon-alpha in the treatment of chronic hepatitis B in the United States.

OBJECTIVE: To determine whether lamivudine or interferon-alpha (IFN-alpha) is the more successful treatment for chronic hepatitis B given a fixed drug budget. STUDY DESIGN: A decision-tree model of 1 year. PATIENTS AND METHODS: Average wholesale prices were used to estimate drug costs. A fixed drug budget of $558,910, sufficient to treat 100 patients with IFN-alpha, was assumed. Clinical data were taken from randomized controlled trials. The outcome measures used were hepatitis B "e" antigen (HBeAg) seroconversion rates and rates of progression to cirrhosis. RESULTS: The analysis showed that given the fixed drug budget, 353 patients could be treated with lamivudine, resulting in an expected 62 HBeAg seroconversions, with 6 patients progressing to cirrhosis. Given the same drug budget, 100 patients could be treated with IFN-alpha, leaving 253 patients untreated. This treatment scenario would result in an expected 32 HBeAg seroconversions, with 28 patients progressing to cirrhosis. Compared with no treatment, the costs per additional HBeAg seroconversion obtained were $12,703 for lamivudine and $39,922 for IFN-alpha. In addition, each case of cirrhosis avoided through lamivudine treatment resulted in significant annual cost savings. Lamivudine therapy also provided additional clinical benefits (e.g., normalization of alanine transaminase levels, reduction in hepatitis B virus DNA levels, improvement in liver histology) to patients who do not seroconvert. CONCLUSION: From the perspective of a third-party payer with a fixed drug budget, lamivudine is more cost-effective therapy than IFN-alpha for the treatment of chronic hepatitis B.

The role of retroviral dUTPases in replication and virulence.

Several retroviruses, including equine infectious anemia virus (EIAV), visna virus, caprine arthritis-encephalitis virus (CAEV) and feline immunodeficiency virus (FIV) encode dUTPase. The role of this enzyme in the replication of these viruses has been scrutinized, with particular emphasis on potential roles for dUTPase in virulence and viral mutation rate. Overall, the results of these studies have indicated a central role for dUTPase in facilitating productive viral replication in non-dividing cells. The requirement for dUTPase in EIAV, which replicates exclusively in macrophages, may be the most stringent. Studies of dUTPase mutants of virulent EIAV clones suggest that the enzyme is a major determinant of virulence. In contrast, FIV readily replicates in dividing cell populations such as CD4+ and CD8+ T cells, and B cells as well as in non-dividing macrophages. Thus, the virus burden and disease sequelae are lowered in cats infected with a dUTPase-minus FIV relative to cats infected with wild type FIV, but not totally abrogated. Growth in macrophages is attenuated with the DU-minus FIV with evidence of a 5 to 8-fold increase in G-->A transition mutations in viral integrants present in macrophages. These findings are consistent with an increase in uracil misincorporation in the absence of dUTPase, resulting in transition mutations that cripple the virus. Effects on virus replication and disease production have also been noted for dUTPase-deleted CEAV and visna virus. While HIV and SIV do not encode dUTPase some reports suggest that other viral and host cell factors may substitute for its activity. Betaretroviruses also encode dUTPase and while several of these cause significant disease, the role of dUTPase in their replication and pathogenesis is currently unknown.

Long terminal repeat sequences of equine infectious anaemia virus are a major determinant of cell tropism.

The Wyoming strain of equine infectious anaemia virus (EIAV) is a highly virulent field strain that replicates to high titre in vitro only in primary equine monocyte-derived macrophages. In contrast, Wyoming-derived fibroblast-adapted EIAV strains (Malmquist virus) replicate in primary foetal equine kidney and equine dermis cells as well as in the cell lines FEA and Cf2Th. Wyoming and Malmquist viruses differ extensively both in long terminal repeat (LTR) and envelope region sequences. We have compared the promoter activities of the Wyoming LTR with those of LTRs derived from fibroblast-adapted viruses by examining their abilities to drive a luciferase reporter gene as well as by construction of infectious molecular clones differing only in LTR sequence. Our results indicate that LTR sequences are a major restriction for growth of the Wyoming strain of EIAV in fibroblasts.

Disease induction by virus derived from molecular clones of equine infectious anemia virus.

Equine infectious anemia virus (EIAV), a macrophage-tropic lentivirus, causes persistent infections of horses. A number of biologic features, including the rapid development of acute disease, the episodic nature of chronic disease, the propensity for viral genetic variation, and the ability for many infected animals to eventually control virus replication, render EIAV a potentially useful model system for the testing of antiretroviral therapies and vaccine strategies. The utility of the EIAV system has been hampered by the lack of proviral clones that encode promptly pathogenic viral stocks. In this report, we describe the generation and characterization of two infectious molecular clones capable of causing acute clinical syndromes similar to those seen in natural infections. Virus derived from clone p19/wenv17 caused severe debilitating disease at 5 to 7 days postinfection; initial febrile episodes were fatal in two of three infected animals. Virus derived from a second clone, p19/wenv16, caused somewhat milder primary febrile episodes by 10 to 12 days postinfection in two of two infected animals. Virus derived from both clones caused persistent infections such that some animals exhibited chronic equine infectious anemia, characterized by multiple disease episodes. The two virulent clones differ in envelope and rev sequences.

Characterization and mutational studies of equine infectious anemia virus dUTPase.

The macrophage tropic lentivirus, equine infectious anemia virus (EIAV), encodes a dUTPase in the pol gene that is required for efficient replication in macrophages. Two naturally occurring variants of the enzyme were expressed as recombinant proteins in Escherichia coli; metal chelate affinity chromatography was used to purify histidine-tagged recombinant enzymes to greater than 80% homogeneity in a single chromatographic step. Biochemical and enzymatic analyses of these preparations suggest that this method yields dUTPase that is suitable for detailed mutational analysis. Specific activities of preparations ranged from 4 x 10(3) to 5 x 10(4) units/mg. Recombinant EIAV dUTPase was highly specific for dUTP with a Km in the range of 3 to 8 microM. The enzyme was sensitive to inhibition by dUDP with little inhibition by other nucleotides or the reaction products, dUMP and PPi. The subunit organization of recombinant EIAV dUTPase was probed by gel filtration, glycerol gradient centrifugation, and chemical cross-linking, and is a trimer. We have begun mutational analyses by targeting a conserved domain present at the carboxyl terminus of all dUTPases that shares high homology to the phosphate binding loops (P-loops) of a number of ATP- and GTP-binding phosphatases. The P-loop-like motif of dUTPases is glycine rich but lacks the invariant lysine found in authentic P-loops. Deletion of this motif leads to loss of dUTPase activity; a series of point mutations that have been shown to inactivate authentic P-loops also abolish EIAV dUTPase activity.

Activation of two sites by adenosine receptor agonists to cause relaxation in rat isolated mesenteric artery.

1. In this study we have characterized the receptor(s) in the rat mesenteric artery mediating relaxant responses to adenosine and a number of adenosine analogues, N6-R-phenylisopropyladenosine (R-PIA), N6-cyclopentyladenosine (CPA), N6-(3-iodo-benzyl)-adenosine-5'-N-methyluronamide (IB-MECA) and 5'-N-ethylcarboxamidoadenosine (NECA), by use of the non-selective antagonist 8-sulphophenyltheophylline (8-SPT) and the A2A selective ligands 2-[p-(2-carbonylethyl)-phenylethylamino]-5'-N-ethylcarboxami doadenosine (CGS 21680) and 4-(2-[7-amino-2-(2-furyl)[1,2,4]-triazolo[2,3-a][1,3,5]-triazin-5- ylamino]ethyl) phenol (ZM 241385). We have also studied the effects of endothelial removal and uptake inhibition by nitrobenzylthioinosine (NBTI) and the effects of the A3 receptor antagonist 1,3-dipropyl-8-(4-acrylate)phenylxanthine (BWA1433). 2. Adenosine, NECA, CPA and R-PIA all elicited relaxant responses in tissues precontracted with phenylephrine (1 microM) with the following potency order: NECA > R-PIA > adenosine = CPA. However, E/[A] curves to NECA were biphasic. CGS 21680 was inactive at concentrations up to 30 microM and IB-MECA elicited relaxant responses which were resistant to blockade by 8-SPT and BWA1433 (100 microM). 3. Removal of the endothelium produced a small but significant decrease in the asymptote of the high potency phase of E/[A] curves to NECA with no change in p[A]50. E/[A] curves to adenosine were not altered by removal of the endothelium. However, there were small rightward shifts of E/[A] curves to CPA and R-PIA in the absence of endothelium. 4. Inhibition of uptake by NBTI (1 microM) had no effect on E/[A] curves to NECA, CPA or R-PIA, but E/[A] curves to adenosine were significantly left-shifted in the presence of NBTI. 5. 8-SPT (10-100 microM) caused significant rightward shifts of the high potency phase of the E/[A] curves to NECA (pA2 = 5.63+/-0.26). The second phase of the concentration-response curve to NECA appeared to be resistant to blockade by 8-SPT, as were E/[A] curves for adenosine, CPA or R-PIA. However, in the presence of NBTI (1 microM), 8-SPT (100 microM) gave significant rightward shifts of E/[A] curves to adenosine. 6. ZM 241385 (0.1-1 microM) produced significant rightward shifts of the high potency phase of NECA E/[A] curves (pA2=7.65+/-0.25 in the presence and 7.20+/-0.12 in the absence of endothelium), while curves to R-PIA were not significantly shifted by 1 microM ZM 241385. In the presence of NBTI E/[A] curves to adenosine were significantly rightward shifted by ZM 241385 (0.1 microM, pA2=7.50+/-0.16). 7. In conclusion, the results suggest activation of A2B receptors located primarily on the smooth muscle by low concentrations of NECA and by adenosine under conditions of uptake blockade, and of another, as yet undefined site which may be intracellular, by higher concentrations of NECA, by CPA, R-PIA and adenosine under conditions where uptake is operational.

Expression, characterisation and mutagenesis of the aspartic proteinase from equine infectious anaemia virus.

The gene encoding the proteinase from equine infectious anaemia virus (EIAV) was cloned and expressed in Escherichia coli. The recombinant EIAV proteinase was purified to homogeneity and shown to have the ability to process polyprotein and synthetic peptide substrates of human immunodeficiency virus (HIV) origin with an efficiency that can approach that exhibited by HIV proteinase. EIAV proteinase, however, was not susceptible to inhibition by a wide variety of inhibitors of HIV-1 proteinase, including those which have been licenced as anti-AIDS drugs. In this respect, EIAV proteinase behaves like an extreme case of a drug-resistant mutant of HIV-1 proteinase that has arisen under selective drug pressure. Only one potent inhibitor (HBY-793) of HIV-1 proteinase showed comparable efficiency against the EIAV enzyme; the compounds A-77003 and A-76889, which differ only in their stereochemistry and which are otherwise structurally identical to HBY-793 from residues P2 to P2' [nomenclature of Schechter, I. & Berger, A. (1967) Biochem. Biophys. Res. Commun. 27, 157-162], were not effective inhibitors of EIAV proteinase. Mutant forms of EIAV proteinase (Thr30-->Asp and Ile54-->Gly) were generated and their ability to interact with substrates and inhibitors was characterised. HBY-793 inhibited [Gly54]proteinase as effectively as the wild-type proteinase but was tenfold less potent against [Asp30]proteinase. Data interpretations are presented, based on the structure solved for the complex between HBY-793 and EIAV [Gly54]proteinase [Gustchina A., Kervinen, J., Powell, D. J., Zdanov, A., Kay, J. & Wlodawer, A. (1996) Protein Sci. 5, 1453-1465].

Incorporation of uracil into viral DNA correlates with reduced replication of EIAV in macrophages.

The retrovirus equine infectious anemia virus (EIAV) encodes a dUTPase situated between reverse transcriptase and integrase. We have described the inability of EIAV with a 270-bp dUTPase deletion, delta DU EIAV, to replicate to wild-type (WT) levels in equine macrophages (D. S. Threadgill, W. K. Steagall, M. T. Flaherty, F. J. Fuller, S. T. Perry, K. E. Rushlow, S. F. J. LeGrice, and S. L. Payne, J. Virol. 67, 2592-2600, 1993). Here we describe the construction of a second dUTPase-deficient virus (DUD71E) containing a single amino acid substitution in dUTPase. delta DU and DUD71E replicate to 2% of WT levels in macrophages by 7 days postinfection, when WT EIAV is highly cytopathic. To identify the replication block(s), we analyzed DNA synthesis, integration, and transcription. DNA synthesis was normal in macrophages, with evidence of full-length viral DNA by 24 hr postinfection. The level of integrated delta DU and DUD71E DNA appeared to be decreased 2- to 3-fold compared to WT. Steady-state levels of full-length viral transcripts were decreased over 100-fold, indicating that replication of dUTPase-deficient EIAV is blocked between viral DNA synthesis and transcription. As dUTP hydrolysis normally plays a role in preventing incorporation of uracil into newly synthesized DNA, we investigated the possibility that dUTPase-deficient EIAV DNA contains uracil. In vitro assays showed that while WT virions do not utilize dUTP, dUTPase-deficient virus and recombinant RT synthesize uracil-containing DNA. The presence of uracil in viral DNA recovered from delta DU- and DUD71E-infected macrophages was also demonstrated. In macrophages, a virally encoded dUTPase may be necessary to prevent the incorporation of uracil into viral DNA.

A comparison of fluticasone propionate 200 micrograms/day with beclomethasone dipropionate 400 micrograms/day in adult asthma.

A total of 261 patients with symptomatic, mild to moderate asthma were randomized to treatment in this 4-week, double-blind, parallel-group comparison of fluticasone propionate 200 micrograms/d with beclomethasone dipropionate 400 micrograms/d. Improvements from both treatments were seen in diary card data. Morning peak expiratory flow rate (PEFR) improved from 375 to 390 and 371 to 382 l/min with fluticasone propionate and beclomethasone dipropionate, respectively. Symptom scores, percentage of symptom-free days and nights, and use of rescue beta 2-agonist medication also improved, as did clinical lung function. With the exception of percentage of rescue-free days, which was greater for beclomethasone dipropionate, none of the differences between the groups were statistically significant. There was a significant difference between treatments in the number of rescue-free days over days 1-28; however, there was no difference between treatments in the number of rescue-free days over days 1-14, nor was there any difference in the number of inhalations of rescue medication used throughout the study. Very few adverse effects were reported. Although all mean plasma cortisol values were within the normal range, they were significantly different between treatments, rising from 402 to 429 nmol/l with fluticasone propionate, and falling from 435 to 394 nmol/l with beclomethasone dipropionate (P = 0.006). Mean stimulated cortisol levels 30 min after tetracosactin injection were also significantly greater with fluticasone propionate (P = 0.024). In conclusion, fluticasone propionate 200 micrograms/d is as effective as beclomethasone dipropionate 400 micrograms/d with less effect on plasma cortisol levels.

Characterization of infectious molecular clones of equine infectious anaemia virus.

We have recovered five infectious molecular clones of the lentivirus equine infectious anaemia virus (EIAV). The clones were recovered from fetal equine kidney (FEK) cells infected with a virulent, cell culture-adapted virus stock (designated PV) and have been characterized at a molecular level. Each clone has unique envelope and long terminal repeat (LTR) sequences. We further investigated LTR sequence variation in the PV stock using PCR amplification to obtain additional LTR clones from infected FEK cells and from peripheral blood mononuclear cells (PBMCs) from animals experimentally infected with PV. Sequence analysis of resulting clones indicates a selection for different LTR populations in pony PBMCs compared to FEK cells. Finally, we observed that the cloned EIAV proviruses did not remain infectious when maintained in a derivative of pBR322. However, two proviruses have been stably maintained in a low copy number vector (pLG338-SPORT).

A comparison of fluticasone propionate, 1 mg daily, with beclomethasone dipropionate, 2 mg daily, in the treatment of severe asthma. International Study Group.

We wanted to compare the efficacy and safety of fluticasone propionate, a new topically active inhaled corticosteroid, to that of high dose beclomethasone dipropionate, in severe adult asthma. Patients currently receiving between 1.5-2.0 mg.day-1 of an inhaled corticosteroid were treated for six weeks in a double-blind, randomized, parallel group study with 1 mg.day-1 fluticasone propionate (n = 82), or 2 mg.day-1 beclomethasone dipropionate (n = 72). Mean morning peak expiratory flow rates (PEFR) increased from 303 to 321 l.min-1 with fluticasone propionate, and from 294 to 319 l.min-1 with beclomethasone dipropionate. There was an increase in evening PEFR, asthma symptoms improved, and rescue beta 2-agonist use decreased for both treatment groups. None of these differences between treatments were statistically significant. However, diurnal variation was significantly reduced with fluticasone propionate, when compared with beclomethasone dipropionate (difference = 7 l.min-1; p = 0.038). Clinic lung function also improved with both treatments and, apart from % predicted PEFR, which showed no difference after beclomethasone dipropionate but increased from 73 to 78% with fluticasone propionate, there were no differences between treatments. Forced expiratory volume in one second (FEV1) increased with both treatments. The geometric mean plasma cortisol concentration rose after treatment with fluticasone propionate (from 293 to 309 nmol.l-1) and fell after beclomethasone dipropionate (from 256 to 224 nmol.l-1); the difference between treatments was significant. The incidence of adverse events was low in both treatment groups. In conclusion, 1 mg.day-1 fluticasone propionate was as effective as 2 mg.day-1 beclomethasone dipropionate in the control of severe asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of equine infectious anemia virus dUTPase: growth properties of a dUTPase-deficient mutant.

The putative dUTPase domain was deleted from the polymerase (pol) gene of equine infectious anemia virus (EIAV) to produce a recombinant delta DUpol Escherichia coli expression cassette and a delta DU proviral clone. Expression of the recombinant delta DUpol polyprotein yielded a properly processed and enzymatically active reverse transcriptase, as determined by immunoblot analysis and DNA polymerase activity gels. Transfection of delta DU provirus into feline (FEA) cells resulted in production of virus that replicated to wild-type levels in both FEA cells and fetal equine kidney cells. In contrast, the delta DU virus replicated poorly (less than 1% of wild-type levels) in primary equine macrophage cultures, as measured by reverse transcriptase assays. Preparations of delta DU virus contained negligible dUTPase activity, which confirms that virion-associated dUTPase is encoded in the pol gene region between the RNase H domain and integrase, as has been demonstrated previously for feline immunodeficiency virus (J. H. Elder, D. L. Lerner, C. S. Hasselkus-Light, D. J. Fontenot, E. Hunter, P. A. Luciw, R. C. Montelaro, and T. R. Phillips, J. Virol. 66:1791-1794, 1992). Our results suggest that virus-encoded dUTPase is dispensable for virus replication in dividing cells in vitro but may be required for efficient replication of EIAV in nondividing equine macrophages, the natural host cells for this virus.