S100A1: a regulator of myocardial contractility

S100A1, a Ca(2+) binding protein of the EF-hand type, is preferentially expressed in myocardial tissue and has been found to colocalize with the sarcoplasmic reticulum (SR) and the contractile filaments in cardiac tissue. Because S100A1 is known to modulate SR Ca(2+) handling in skeletal muscle, we sought to investigate the specific role of S100A1 in the regulation of myocardial contractility. To address this issue, we investigated contractile properties of adult cardiomyocytes as well as of engineered heart tissue after S100A1 adenoviral gene transfer. S100A1 gene transfer resulted in a significant increase of unloaded shortening and isometric contraction in isolated cardiomyocytes and engineered heart tissues, respectively. Analysis of intracellular Ca(2+) cycling in S100A1-overexpressing cardiomyocytes revealed a significant increase in cytosolic Ca(2+) transients, whereas in functional studies on saponin-permeabilized adult cardiomyocytes, the addition of S100A1 protein significantly enhanced SR Ca(2+) uptake. Moreover, in Triton-skinned ventricular trabeculae, S100A1 protein significantly decreased myofibrillar Ca(2+) sensitivity ([EC(50%)]) and Ca(2+) cooperativity, whereas maximal isometric force remained unchanged. Our data suggest that S100A1 effects are cAMP independent because cellular cAMP levels and protein kinase A-dependent phosphorylation of phospholamban were not altered, and carbachol failed to suppress S100A1 actions. These results show that S100A1 overexpression enhances cardiac contractile performance and establish the concept of S100A1 as a regulator of myocardial contractility. S100A1 thus improves cardiac contractile performance both by regulating SR Ca(2+) handling and myofibrillar Ca(2+) responsiveness.

Lessons learned from the national heart failure project: a center for medicare and medicaid services initiative to improve the care of medicare beneficiaries with heart failure

This column is the seventh in a series reporting on the efforts of the Center for Medicare and Medicaid Services (CMS), formerly known as the Health Care Financing Administration, to improve care for Medicare beneficiaries with heart failure. In previous columns we have described the overall structure of Medicare quality improvement efforts, detailed the structure of the national inpatient fee-for-service program known as the National Heart Failure project, and discussed the baseline quality indicator rates for the project, which are focused on rates of ejection fraction documentation and angiotensin-converting enzyme inhibitor prescription. In more recent columns, we reported on quality improvement projects from several participating hospitals, and on a pilot project exploring quality improvement efforts for heart failure based in physicians' offices. This column will focus on ways in which systematic examination of data, such as those from the National Heart Failure project, might shape future quality improvement and research efforts. The National Heart Failure project's quality indicator data are collected primarily to guide and evaluate the efforts of the CMS contractor peer-review organizations to facilitate quality improvement efforts in hospitals throughout the United States. (c)2001 CHF, Inc.

Human cortical processing of colour and pattern

The present study investigates human visual processing of simple two-colour patterns using a delayed match to sample paradigm with positron emission tomography (PET). This study is unique in that we specifically designed the visual stimuli to be the same for both pattern and colour recognition with all patterns being abstract shapes not easily verbally coded composed of two-colour combinations. We did this to explore those brain regions required for both colour and pattern processing and to separate those areas of activation required for one or the other. We found that both tasks activated similar occipital regions, the major difference being more extensive activation in pattern recognition. A right-sided network that involved the inferior parietal lobule, the head of the caudate nucleus, and the pulvinar nucleus of the thalamus was common to both paradigms. Pattern recognition also activated the left temporal pole and right lateral orbital gyrus, whereas colour recognition activated the left fusiform gyrus and several right frontal regions.

A prime-boost immunisation regimen using DNA followed by recombinant modified vaccinia virus Ankara induces strong cellular immune responses against the Plasmodium falciparum TRAP antigen in chimpanzees

Two chimpanzees were vaccinated intramuscularly against malaria using plasmid DNA expressing the pre-erythrocytic antigens thrombospondin related adhesion protein (PfTRAP) and liver stage specific antigen-1 (PfLSA-1) of Plasmodium falciparum together with GM-CSF protein. A recombinant modified vaccinia virus Ankara (MVA) expressing PfTRAP was injected intramuscularly 6 weeks later to boost the immune response. This sequence of antigen delivery induced a specific and long-lasting T cell and antibody response to PfTRAP as detected by ELISPOT assay and ELISA. Antibody responses were detected after four DNA injections, and were boosted by injection of recombinant MVA expressing PfTRAP. Interferon-gamma secreting antigen-specific T cells were detected in both animals, but only after boosting with recombinant MVA. By screening a panel of PfTRAP-derived peptides, an epitope was identified that was recognized by cytotoxic T lymphocytes in one of the chimpanzees studied. T cells specific for this epitope were present in PBMCs and liver-infiltrating lymphocytes at a frequency of between 1 in 200 and 1 in 500. The high immunogenicity of this prime-boost regimen in chimpanzees supports further assessment of this delivery strategy for the induction of protection against P. falciparum malaria in humans.

Dual X-ray absorptiometry detects disease- and treatment-related alterations of bone density in prostate cancer patients

Metastatic bone disease is an important clinical problem which has proven difficult to study because of a lack of noninvasive investigative modalities. Here we show that dual-energy X-ray absorptiometry (DXA) scanning provides clinically useful information about the status of metastatic bone lesions in cancer patients undergoing palliative treatment. In the study group of 21 patients, a significant increase in metastatic bone mineral density (BMD) was confirmed in prostate (n = 14) relative to breast (n = 7) cancer patients. With respect to the prostate cancer cohort, further increases in lesional BMD were evident in all evaluable patients in whom biochemical progression occurred; conversely, lesional BMD declined in patients who had a partial response to therapy. BMD of uninvolved bone decreased with all types of androgen-deprivation therapy regardless of whether patients responded or relapsed. We conclude that BMD changes in both lesional and uninvolved bone are readily detectable in metastatic prostate cancer, and propose that DXA scanning represents a promising new approach to monitoring the natural history and therapeutic course of this disease.

Predictors of costs of caring for elderly patients discharged with heart failure

BACKGROUND

Investments in programs to improve outcomes and reduce readmissions for patients who survive hospitalization with heart failure will be economically most favorable for those who have the highest risk. Little information is available, however, to stratify the risk of these patients incurring costs after discharge. In this study, we sought to determine correlates of costs in a representative sample of patients with heart failure in the 6 months after discharge.

METHODS

We reviewed medical records of 2181 patients aged > or = 65 years who were discharged alive from 18 Connecticut hospitals in 1994 and 1995 with a principal discharge diagnosis of heart failure. Outcomes 6 months after discharge, including all-cause readmission and cost, heart failure-related readmission and cost, and death, were obtained from the Medicare administrative database. A 2-stage sample selection model was used to identify the independent correlates of cost. Risk scores were calculated to identify subsets of patients at risk for generating high costs.

RESULTS

On average, patients discharged with heart failure incurred costs of $2388 resulting from heart failure-related admissions and $7101 resulting from admissions from any cause during the 6 months after discharge. An average admission for heart failure cost $7174, whereas an admission resulting from any cause cost $8589. The multivariate models explained 7% of the variation in cost, although clinical characteristics such as recent heart failure admissions, kidney failure, and hypertension were significant independent correlates of increased cost. Older age and a history of stroke were independently associated with decreased cost. Patients without any of the risk factors associated with increased costs still incurred $1500 to $5000, on average, in the 6 months after discharge.

CONCLUSIONS

Patients with heart failure generate substantial hospital costs in the 6 months after discharge. Given the emerging evidence for effective programs to reduce readmission, investments in interventions that produce even modest reductions in risk would be economically favorable.

The vaccinia virus superoxide dismutase-like protein (A45R) is a virion component that is nonessential for virus replication

A characterization of the A45R gene from vaccinia virus (VV) strain Western Reserve is presented. The open reading frame is predicted to encode a 125-amino-acid protein (M(r), of 13,600) with 39% amino acid identity to copper-zinc superoxide dismutase (Cu-Zn SOD). Sequencing of the A45R gene from other orthopoxviruses, here and by others, showed that the protein is highly conserved in all viruses sequenced, including 16 strains of VV, 2 strains of cowpox virus, camelpox virus, and 4 strains of variola virus. In all cases the protein lacks key residues involved in metal ion binding that are important for the catalytic activity. The A45R protein was expressed in Escherichia coli, purified, and tested for SOD activity, but neither enzymatic nor inhibitory SOD activity was detected. Additionally, no virus-encoded SOD activity was detected in infected cells or purified virions. A monoclonal antibody raised against the A45R protein expressed in E. coli identified the A45R gene product as a 13.5-kDa protein that is expressed late during VV infection. Confocal microscopy of VV-infected cells indicated that the A45R protein accumulated predominantly in cytoplasmic viral factories. Electron microscopy and biochemical analyses showed that the A45R protein is incorporated into the virion core. A deletion mutant lacking the majority of the A45R gene and a revertant virus in which the deleted gene was restored were constructed and characterized. The growth properties of the deletion mutant virus were indistinguishable from those of wild-type and revertant viruses in all cell lines tested, including macrophages. Additionally, the virulence and pathogenicity of the three viruses were also comparable in murine and rabbit models of infection. A45R is unusual in being the first VV core protein described that affects neither virus replication nor virulence.

Vaccinia virus utilizes microtubules for movement to the cell surface

Vaccinia virus (VV) egress has been studied using confocal, video, and electron microscopy. Previously, intracellular-enveloped virus (IEV) particles were proposed to induce the polymerization of actin tails, which propel IEV particles to the cell surface. However, data presented support an alternative model in which microtubules transport virions to the cell surface and actin tails form beneath cell-associated enveloped virus (CEV) particles at the cell surface. Thus, VV is unique in using both microtubules and actin filaments for egress. The following data support this proposal. (a) Microscopy detected actin tails at the surface but not the center of cells. (b) VV mutants lacking the A33R, A34R, or A36R proteins are unable to induce actin tail formation but produce CEV and extracellular-enveloped virus. (c) CEV formation is inhibited by nocodazole but not cytochalasin D or 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine (PP1). (d) IEV particles tagged with the enhanced green fluorescent protein fused to the VV B5R protein moved inside cells at 60 microm/min. This movement was stop-start, was along defined pathways, and was inhibited reversibly by nocodazole. This velocity was 20-fold greater than VV movement on actin tails and consonant with the rate of movement of organelles along microtubules.

Molecular marker expression in oral and oropharyngeal squamous cell carcinoma

OBJECTIVE

To determine the relative prognostic value of p53, cyclin D1, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) expression in patients with oral and oropharyngeal squamous cell carcinoma.

DESIGN

Retrospective cohort study.

PATIENTS

Fifty-six patients with oral and oropharyngeal squamous cell carcinoma referred to the Department of Therapeutic Radiology at Yale-New Haven Hospital (Conn) between 1981 and 1992 who were treated with gross total surgical resection and postoperative external beam radiotherapy.

RESULTS

Archival tumor tissue was stained with monoclonal antibodies directed against these 4 oncoproteins and scored for staining intensity and percent distribution by a pathologist blinded to the patients' clinical outcomes. Frequency of marker expression was 48% for p53, 20% for cyclin D1, 64% for EGFR, and 41% for VEGF. In multivariate analysis, EGFR positivity was protective against locoregional relapse (relative risk [RR], 0.27; 95% confidence interval [CI], 0.11-0.66; P =.002). In contrast, advanced N stage predicted poor locoregional relapse-free survival (RR, 1.94; 95% CI, 1.03-3.66; P =.04). Predictors of poor overall survival in multivariate analysis included VEGF positivity (RR, 3.53; 95% CI, 1.75-7.13; P<.001) and black race (RR, 2.48; 95% CI, 1.05-5.85; P =.04). Cyclin D1 and p53 expression were not significantly associated with prognosis in this cohort.

CONCLUSIONS

In oral and oropharyngeal squamous cell carcinoma treated with surgery and postoperative radiotherapy, VEGF and EGFR expression may influence clinical outcome. If confirmed, these results have potential implications for the determination of patient prognosis and the development of biologically based pharmacotherapies.

A comparison of the effects of ATP and tetracaine on spontaneous Ca(2+) release from rat permeabilised cardiac myocytes

1. Fluo-3 fluorescence measurements were made in isolated beta-escin permeablised rat cardiac myocytes using confocal microscopy. Perfusion of a mock intracellular solution containing 0.22-0.23 microM Ca(2+) and 5 mM ATP elicited regular waves of Ca(2+) (approximately every 5 s) due to spontaneous release of Ca(2+) from the sarcoplasmic reticulum (SR). 2. An approximately linear relationship was noted between Ca(2+) wave velocity (v) and amplitude (sigma). Under the control conditions the ratio of velocity to amplitude (v/sigma) varied little and was 99.8 +/- 2.5 m s(-1) microM(-1) (n = 78). 3. Reduction of [ATP] in the bathing solution to 0.5 and 0.2 mM ATP progressively decreased Ca(2+) wave frequency and propagation velocity while increasing the amplitude. The changes in Ca(2+) wave characteristics in 0.5 mM ATP were similar to those observed during perfusion with 50 microM tetracaine. In 0.2 mM ATP the decline of [Ca(2+)] during a Ca(2+) wave was slowed suggesting a lowered rate of Ca(2+) re-uptake by the SR Ca(2+) pump. 4. Reduction of [ATP] to 0.1 mM abolished Ca(2+) waves after 15-20 s. Returning the [ATP] to 5 mM caused a burst of high frequency and large amplitude waves. Mean velocity of the first wave on returning to 5 mM ATP was larger than normal but the v/sigma value was 32 +/- 6 % of control (n = 6). In the similar burst on removal of 100 microM tetracaine v/sigma was higher than control (166 +/- 9 %, n = 6). 5. Rapid application of caffeine (10 mM) was used to assess the SR Ca(2+) content. This showed that SR Ca(2+) increased as [ATP] was reduced or [tetracaine] was increased. The highest SR Ca(2+) content was observed after perfusion with 0.1 mM ATP, which was 245 +/- 15 % of control values. 6. Returning [ATP] from 0.1 mM to 5 mM caused a burst of high frequency, large amplitude Ca(2+) waves. But recovery after incubation with 300 microM tetracaine resulted in SR Ca(2+) release with no coherent wave pattern. The reason for this discrepancy is discussed.

Expression of the developmental and oncogenic PAX2 gene in human prostate cancer

PURPOSE

In the human prostate cancer cell lines LNCaP, DU145 and PC3, 27 primary prostate cancers, 10 benign prostatic hyperplasia specimens and 5 normal prostates we investigated the expression pattern of PAX2, a member of the PAX family of developmental control genes. PAX2 is expressed at high levels in developing undifferentiated cells of the urogenital system and is repressed upon terminal differentiation with no expression in normal adult cells. It is also been shown to be a proto-oncogene in mice and is expressed in human renal cell carcinoma.

MATERIALS AND METHODS

PAX2 expression was assessed at the RNA level by reverse transcriptase-polymerase chain reaction and Southern blot analysis using specific sets of nucleotides. The expression pattern of PAX2 was reconfirmed at the protein level by immunofluorescence in the cell lines, and by Western blot analysis in primary human prostate cancers and benign prostatic tissue.

RESULTS

Using reverse transcription-polymerase chain reaction combined with Southern hybridization PAX2 expression was detected in 52% of primary cancers and all 3 cell lines. PAX2 expression in these samples was confirmed at a protein level using immunoblotting and immunofluorescence. PAX2 messenger RNA was not detected in any benign or normal prostatic samples. Immunoblotting of protein from benign prostatic hyperplasia samples confirmed the lack of expression of PAX2 protein.

CONCLUSIONS

The expression of PAX2 in prostate cancer compared to nonmalignant prostates is statistically significant (Fisher's exact test p = 0.0004). These results suggest a possible role for PAX2 in prostate cancer. Although previous studies have suggested a role for PAX2 for supporting proliferation in undifferentiated cells, no correlation of PAX2 expression with Gleason score was found in prostate cancer.

The genome sequence of Yaba-like disease virus, a yatapoxvirus

The genome sequence of Yaba-like disease virus (YLDV), an unclassified member of the yatapoxvirus genus, has been determined. Excluding the terminal hairpin loops, the YLDV genome is 144,575 bp in length and contains inverted terminal repeats (ITRs) of 1883 bp. Within 20 nucleotides of the termini, there is a sequence that is conserved in other poxviruses and is required for the resolution of concatemeric replicative DNA intermediates. The nucleotide composition of the genome is 73% A+T, but the ITRs are only 63% A+T. The genome contains 151 tightly packed open reading frames (ORFs) that either are > or =180 nucleotides in length or are conserved in other poxviruses. ORFs within 23 kb of each end are transcribed toward the termini, whereas ORFs within the central region of the genome are encoded on either DNA strand. In the central region ORFs have a conserved position, orientation, and sequence compared with vaccinia virus ORFs and encode many enzymes, transcription factors, or structural proteins. In contrast, ORFs near the termini are more divergent and in seven cases are without counterparts in other poxviruses. The YLDV genome encodes several predicted immunomodulators; examples include two proteins with similarity to CC chemokine receptors and predicted secreted proteins with similarity to MHC class I antigen, OX-2, interleukin-10/mda-7, poxvirus growth factor, serpins, and a type I interferon-binding protein. Phylogenic analyses indicated that YLDV is very closely related to yaba monkey tumor virus, but outside the yatapoxvirus genus YLDV is more closely related to swinepox virus and leporipoxviruses than to other chordopoxvirus genera.

Overexpression of FK506-binding protein FKBP12.6 in cardiomyocytes reduces ryanodine receptor-mediated Ca(2+) leak from the sarcoplasmic reticulum and increases contractility

The FK506-binding protein FKBP12.6 is tightly associated with the cardiac sarcoplasmic reticulum (SR) Ca(2+)-release channel (ryanodine receptor type 2 [RyR2]), but the physiological function of FKBP12.6 is unclear. We used adenovirus (Ad)-mediated gene transfer to overexpress FKBP12.6 in adult rabbit cardiomyocytes. Western immunoblot and reverse transcriptase-polymerase chain reaction analysis revealed specific overexpression of FKBP12.6, with unchanged expression of endogenous FKBP12. FKBP12.6-transfected myocytes displayed a significantly higher (21%) fractional shortening (FS) at 48 hours after transfection compared with Ad-GFP-infected control cells (4.8+/-0.2% FS versus 4+/-0.2% FS, respectively; n=79 each; P:=0.001). SR-Ca(2+) uptake rates were monitored in beta-escin-permeabilized myocytes using Fura-2. Ad-FKBP12.6-infected cells showed a statistically significant higher rate of Ca(2+) uptake of 0.8+/-0.09 nmol/s(-)(1)/10(6) cells (n=8, P:<0.05) compared with 0.52+/-0.1 nmol/s(-)(1)/10(6) cells in sham-infected cells (n=8) at a [Ca(2+)] of 1 micromol/L. In the presence of 5 micromol/L ruthenium red to block Ca(2+) efflux via RyR2, SR-Ca(2+) uptake rates were not significantly different between groups. From these measurements, we calculate that SR-Ca(2+) leak through RyR2 is reduced by 53% in FKBP12.6-overexpressing cells. Caffeine-induced contractures were significantly larger in Ad-FKBP12.6-infected myocytes compared with Ad-GFP-infected control cells, indicating a higher SR-Ca(2+) load. Taken together, these data suggest that FKBP12.6 stabilizes the closed conformation state of RyR2. This may reduce diastolic SR-Ca(2+) leak and consequently increase SR-Ca(2+) release and myocyte shortening.

Antibody neutralization of the extracellular enveloped form of vaccinia virus

The extracellular enveloped form (EEV) of vaccinia virus (VV) is important for the long-range dissemination of the virus inside the host. Early work suggested that both IMV and EEV infectivity could be inhibited by antibodies, although two other studies reported that EEV was resistant to neutralization. Here, we readdressed this question, using four VV-immune antisera and their purified IgG, and showed that EEV infectivity can be inhibited by antibody produced from a live infection in plaque-reduction assays, although EEV is more resistant to neutralization by convalescent antibodies than is IMV. In parallel, indirect immunofluorescent staining and confocal microscopy showed that antibody aggregated EEV and prevented it from binding to cells. Using the IgG and Fab fragments prepared from this antiserum, we tested whether EEV made by VV mutants lacking genes A33R, A34R, A36R, A56R, B5R, F12L, or F13L can be inhibited in plaque-reduction assays. Although vDeltaB5R was slightly more resistant than other mutants, none of these mutants escaped neutralization completely, suggesting that multiple virus proteins are involved in the inhibition. Using an antibody specific to B5R protein and B5R mutants with consecutive short consensus repeat (SCR) domains deleted, the neutralization epitopes on B5R were mapped to within the SCR domain 1.

Vaccinia virus F12L protein is required for actin tail formation, normal plaque size, and virulence

Vaccinia virus gene F12L is shown to encode a 65-kDa protein that is synthesized early and late during infection and that is not modified by glycosylation. Computational sequence comparison revealed that related proteins are encoded by all sequenced chordopoxviruses. A virus deletion mutant lacking the F12L gene (vDeltaF12L) and a revertant virus with the F12L gene reinserted into the deletion mutant (vF12L-rev) were constructed and analyzed. A version of the F12L gene with a C-terminal amino acid tag derived from the influenza virus hemagglutinin and that is recognized by a monoclonal antibody was also inserted into the F12L locus of vDeltaF12L. Loss of the F12L protein reduced the formation of IMV 2-fold, but there was a dramatic (99.5%) reduction in actin tail formation, and the levels of cell-associated enveloped virus and extracellular enveloped virus were reduced 8- to 11-fold and 7-fold, respectively. Consistent with the lack of actin tail formation, vDeltaF12L produced a very small plaque. The vDeltaF12L virus was severely attenuated in vivo, such that a dose of vDeltaF12L 10,000-fold greater than the dose of wild-type virus that induced severe disease was unable to induce disease in mice infected intranasally.

The vaccinia virus soluble alpha/beta interferon (IFN) receptor binds to the cell surface and protects cells from the antiviral effects of IFN

Poxviruses encode a broad range of proteins that interfere with host immune functions, such as soluble versions of receptors for the cytokines tumor necrosis factor, interleukin-1 beta, gamma interferon (IFN-gamma), IFN-alpha/beta, and chemokines. These virus-encoded cytokine receptors have a profound effect on virus pathogenesis and enable the study of the role of cytokines in virus infections. The vaccinia virus (VV) Western Reserve gene B18R encodes a secreted protein with 3 immunoglobulin domains that functions as a soluble receptor for IFN-alpha/beta. We have found that after secretion B18R binds to both uninfected and infected cells. The B18R protein present at the cell surface maintains the properties of the soluble receptor, binding IFN-alpha/beta with high affinity and with broad species specificity, and protects cells from the antiviral state induced by IFN-alpha/beta. VV strain Wyeth expressed a truncated B18R protein lacking the C-terminal immunoglobulin domain. This protein binds IFN with lower affinity and retains its ability to bind to cells, indicating that the C-terminal region of B18R contributes to IFN binding. The replication of a VV B18R deletion mutant in tissue culture was restricted in the presence of IFN-alpha, whereas the wild-type virus replicated normally. Binding of soluble recombinant B18R to cells protected the cultures from IFN and allowed VV replication. This represents a novel strategy of virus immune evasion in which secreted IFN-alpha/beta receptors not only bind the soluble cytokine but also bind to uninfected cells and protect them from the antiviral effects of IFN-alpha/beta, maintaining the cells' susceptibility to virus infections. The adaptation of this soluble receptor to block IFN-alpha/beta activity locally will help VV to replicate in the host and spread in tissues. This emphasizes the importance of local effects of IFN-alpha/beta against virus infections.

Undetectable ultrasensitive PSA after radical prostatectomy for prostate cancer predicts relapse-free survival

Radical retropubic prostatectomy is considered by many centres to be the treatment of choice for men aged less than 70 years with localized prostate cancer. A rise in serum prostate-specific antigen after radical prostatectomy occurs in 10-40% of cases. This study evaluates the usefulness of novel ultrasensitive PSA assays in the early detection of biochemical relapse. 200 patients of mean age 61. 2 years underwent radical retropubic prostatectomy. Levels < or = 0.01 ng ml-1 were considered undetectable. Mean pre-operative prostate-specific antigen was 13.3 ng ml-1. Biochemical relapse was defined as 3 consecutive rises. The 2-year biochemical disease-free survival for the 134 patients with evaluable prostate-specific antigen nadir data was 61.1% (95% CI: 51.6-70.6%). Only 2 patients with an undetectable prostate-specific antigen after radical retropubic prostatectomy biochemically relapsed (3%), compared to 47 relapses out of 61 patients (75%) who did not reach this level. Cox multivariate analysis confirms prostate-specific antigen nadir < or = 0.01 ng ml-1 to be a superb independent variable predicting a favourable biochemical disease-free survival (P < 0.0001). Early diagnosis of biochemical relapse is feasible with sensitive prostate-specific antigen assays. These assays more accurately measure the prostate-specific antigen nadir, which is an excellent predictor of biochemical disease-free survival. Thus, sensitive prostate-specific antigen assays offer accurate prognostic information and expedite decision-making regarding the use of salvage prostate-bed radiotherapy or hormone therapy.

Recombinant modified vaccinia virus Ankara efficiently restimulates human cytotoxic T lymphocytes in vitro

The immunogenicity of recombinant modified vaccinia Ankara, a highly attenuated vaccinia virus, expressing influenza nucleoprotein (MVA-NP) and HIV-1 gag (MVA-gag) was investigated. Restimulation of peripheral blood lymphocytes of healthy subjects with MVA-NP led to expansion of CTL with specificity for known NP epitopes. These CTL efficiently lysed NP peptide-pulsed targets and released interferon-gamma (IFN-gamma) on contact with epitope peptide. MVA-NP-stimulated CTL specific for the HLA-B8 epitope, NP380-88, stained with a tetrameric complex of HLA-B8 refolded with the NP380-88 peptide and anti-CD8 antibody on flow cytometry. CTL were also elicited from two HIV-1 seropositive donors by restimulation with MVA-HIV-1 gag and showed specificity for immunodominant gag epitopes. These data indicate that restimulation of human CTL with recombinant MVA is effective and suggest that MVA will elicit CTL responses in humans in vivo.

A46R and A52R from vaccinia virus are antagonists of host IL-1 and toll-like receptor signaling

Poxviruses employ many strategies to evade and neutralize the host immune response. In this study, we have identified two vaccinia virus ORFs, termed A46R and A52R, that share amino acid sequence similarity with the Toll/IL-1 receptor (TIR) domain, a motif that defines the IL-1/Toll-like receptor (TLR) superfamily of receptors, which have a key role in innate immunity and inflammation. When expressed in mammalian cells, the protein products of both ORFs were shown to interfere specifically with IL-1 signal transduction. A46R partially inhibited IL-1-mediated activation of the transcription factor NFkappaB, and A52R potently blocked both IL-1- and TLR4-mediated NFkappaB activation. MyD88 is a TIR domain-containing adapter molecule known to have a central role in both IL-1 and TLR4 signaling. A52R mimicked the dominant-negative effect of a truncated version of MyD88 on IL-1, TLR4, and IL-18 signaling but had no effect on MyD88-independent signaling pathways. Therefore, A46R and A52R are likely to represent a mechanism used by vaccinia virus of suppressing TIR domain-dependent intracellular signaling.

P(i) inhibits the SR Ca(2+) pump and stimulates pump-mediated Ca(2+) leak in rabbit cardiac myocytes

Measurements of sarcoplasmic reticulum (SR) Ca(2+) uptake were made from aliquots of dissociated permeabilized ventricular myocytes using fura 2. Equilibration with 10 mM oxalate ensured a reproducible exponential decline of [Ca(2+)] from 600 nM to a steady state of 100-200 nM after addition of Ca(2+). In the presence of 5 microM ruthenium red, which blocks the ryanodine receptor, the time course of the decline of [Ca(2+)] can be modeled by a Ca(2+)-dependent uptake process and a fixed Ca(2+) leak. Partial inhibition of the Ca(2+) pump with 1 microM cyclopiazonic acid or 50 nM thapsigargin reduced the time constant for Ca(2+) uptake but did not affect the SR Ca(2+) leak. Addition of 10 mM inorganic phosphate (P(i)) decreased the rate of Ca(2+) accumulation by the SR and increased the Ca(2+) leak rate. This effect was reversed on addition of 10 mM phosphocreatine. 10 mM P(i) had no effect on Ca(2+) leak from the SR after complete inhibition of the Ca(2+) pump. In conclusion, P(i) decreases the Ca(2+) uptake capacity of cardiac SR via a decrease in pump rate and an increase in Ca(2+) pump-dependent Ca(2+) leak.

External validity of conduct and oppositional defiant disorders determined by the NIMH Diagnostic Interview Schedule for children

We administered the Diagnostic Interview Schedule for Children (DISC) two times to a group of youth (222 boys, 147 girls) entering residential care, once at their time of entry and once 1 year later. We then compared their DISC outcomes on Conduct Disorder (CD) and Oppositional Defiant Disorder (ODD) against changes in independent direct observations of diagnostically relevant behavior obtained over the course of that year. Results from hierarchical linear modeling analyses showed significant discriminative relationships between results from the DISC and the independent observations. Specifically, observations of symptomatic behaviors (CD or ODD) decreased for youth who met diagnostic criteria at the first administration of the DISC but not at the second, increased for youth who did not meet criteria at the first administration but did at the second, and did not change for youth who met criteria at both administrations. These results extend the data on the validity of the DISC and support continued research efforts to determine its clinical utility.

The vaccinia virus A36R protein is a type Ib membrane protein present on intracellular but not extracellular enveloped virus particles

Vaccinia virus gene A36R encodes a 45-kDa protein that is conserved in orthopoxviruses. A virus lacking the A36R protein formed a small plaque, was unable to induce the polymerization of actin tails, and was avirulent in vivo. Here we present a further characterization of the A36R protein by in vitro transcription and translation and analysis of infected cells by confocal microscopy and immunoelectron microscopy of cryosections using a monoclonal antibody raised against the C-terminal domain of the A36R protein. Translation of the A36R mRNA in vitro produced a protein of the same size whether or not the translation reaction was performed in the presence of canine pancreatic microsomes. However, the polypeptide synthesized in the presence of microsomes was associated integrally with the membrane and was sensitive to digestion by exogenous protease without permeabilization of the membrane with detergent, indicating that the majority of the protein is exposed on the outside of the vesicle. Consistent with this, immunofluorescent analysis of virus-infected cells demonstrated that the C-terminal domain of A36R was not exposed on the cell surface but was detected once the cell membrane was permeabilized. Immunoelectron microscopy of cryosections of infected cells showed that the protein was absent from IMV particles but present on intracellular enveloped virus (IEV) particles, predominantly on the cytosolic face of the IEV outer membrane. Where cell-associated enveloped virus (CEV) particles were attached to the cell surface, the A36R protein was detected only on the cytosolic surface of the plasma membrane where the virus particle remained attached to the cell and not elsewhere on the plasma membrane or on the CEV particle. A36R and actin copurified with EEV particles due to the association of fragments of cellular membranes with the EEV particles. Therefore, A36R represents the first example of a virus-encoded protein that is present on IEV but not CEV particles.

Prognostic significance of vascular endothelial growth factor protein levels in oral and oropharyngeal squamous cell carcinoma

PURPOSE

Vascular Endothelial Growth Factor (VEGF) promotes angiogenesis in many different tumor types. VEGF levels may affect tumor growth, metastatic potential, and response to radiotherapy. This study assesses the prognostic value of VEGF protein levels in a cohort of patients with oral and oropharyngeal squamous cell carcinomas. The relationships between clinical outcome and the covariables of tumor-node-metastasis stage, disease stage (I to IV), grade, margin status, race, sex, and age were also determined.

PATIENTS AND METHODS

Chart review identified 77 patients with oral or oropharyngeal squamous cell carcinoma treated with gross total surgical resection and postoperative radiation between 1981 and 1992. Sufficient follow-up data and tumor tissue were available in 56 patients (73%). VEGF protein levels were determined using immunohistochemistry. The association between VEGF status, covariables, and outcome was assessed in a bivariate and multivariate model using two-sided statistical tests.

RESULTS

Twenty-three tumors (41%) were positive for VEGF expression. VEGF-positive tumors were more likely to recur locally (relative risk [RR] = 3.08; 95% confidence interval [CI], 1.03 to 9.24) and distantly (RR = 4.62; 95% CI, 1.41 to 15.10). In bivariate analysis, VEGF positivity was the most significant predictor of poor disease-free survival (RR = 2.66; 95% CI, 1.27 to 5.56) and overall survival (RR = 3.21; 95% CI, 1.63 to 6.32). In multivariate analysis, VEGF positivity was the most significant predictor of poor disease-free survival (RR = 2.75; 95% CI, 1.30 to 5.79) and overall survival (RR = 3.53; 95% CI, 1.75 to 7.13).

CONCLUSION

In this cohort, VEGF positivity was the most significant predictor of poor prognosis. VEGF status may prove to be an important prognostic factor in head and neck cancer.

Cellular basis for contractile dysfunction in the diaphragm from a rabbit infarct model of heart failure

Abnormal respiratory muscle function is thought to contribute to breathlessness and exercise intolerance in heart failure but little is known about possible alterations in the function of such muscle. We have measured tetanic force and intracellular Ca(2+) concentration ([Ca(2+)](i)) in isolated, arterially perfused hemidiaphragm preparations from a rabbit coronary artery ligation model of heart failure. Increasing stimulation frequency (10-100 Hz) caused a progressive increase of force and [Ca(2+)](i) in control preparations, whereas force and [Ca(2+)](i) only increased between 10 and 25 Hz stimulation (decreasing at higher frequencies) in preparations from ligated animals. Cyclopiazonic acid produced a dose-dependent shift in the relationship between stimulation frequency and [Ca(2+)](i) in control preparations that was similar to the shift observed in the diaphragm of coronary-ligated animals. These data indicate that the in vitro contractile characteristics of the diaphragm are significantly altered in our model and that altered [Ca(2+)](i) regulation contributes to the reduced diaphragm strength observed in heart failure.

Vaccinia virus gene B7R encodes an 18-kDa protein that is resident in the endoplasmic reticulum and affects virus virulence

This paper presents a characterisation of vaccinia virus (VV) gene B7R that was predicted to encode a polypeptide of 182 amino acids with an N-terminal signal peptide. In vitro transcription and translation analysis showed the B7R gene product was a 21-kDa protein that, in the presence of microsomes, was processed into an 18-kDa mature form. The 18-kDa form associated with the microsomal membranes and was within the lumen of the vesicle where it was inaccessible to exogenous protease or an antibody raised against the B7R C terminus. Within VV-infected cells, the 18-kDa form of B7R was detected late during infection in the endoplasmic reticulum where it colocalised with protein disulphide isomerase. The B7R protein was detected neither in the culture supernatant nor associated with virus particles. A virus deletion mutant lacking the B7R gene and a revertant virus were constructed. Compared to wild-type and revertant viruses, the deletion mutant replicated normally in cell culture and had unaltered virulence in a murine intranasal model of infection. However, the deletion mutant was attenuated in a murine intradermal model where it induced a smaller lesion than the control viruses.

Heterogeneous changes in action potential and intracellular Ca2+ in left ventricular myocyte sub-types from rabbits with heart failure

OBJECTIVE

Myocardial cellular electrophysiology and intracellular Ca2+ regulation are altered in heart failure. The extent of these changes may vary within the layers of the ventricular wall. To examine this, cell size, action potential and intracellular Ca2+ transient characteristics (Fura-2) were measured in single cardiac myocytes from sub-epicardial, mid-myocardial, and sub-endocardial regions of the left ventricle of rabbits with heart failure.

METHODS

Myocytes were isolated from animals with heart failure induced by chronic coronary artery ligation and from sham operated controls. Trans-membrane potential was measured using high resistance microelectrodes electrodes (30 M omega; 2 M KC1). Fura-2 was loaded into cells by incubation with the AM form. Subsequent fluorescence measurements were used to measure intracellular Ca2+ concentration at a range of stimulus frequencies.

RESULTS

Resting cell length was significantly greater in the heart failure group; approximately 115% of control values in sub-epicardial and mid-myocardial cells, and approximately 108% in sub-endocardial cells. Using criteria described by previous studies on other mammalian hearts, functional M cells were identified by a higher maximum rate of depolarisation and longer action potential duration at 90% repolarisation (APD90) compared to the two other myocyte sub-types. In the heart failure group, APD90 and Ca2+ transient duration (CaD50) were prolonged in sub-epicardial and M cells but shortened in sub-endocardial myocytes. These changes were significant at lower stimulus frequencies, but the relative effect diminished at higher frequencies (3 Hz). Peak systolic [Ca2+] was reduced in sub-epicardial and M cells but increased in sub-endocardial cells in the heart failure group compared to controls. At higher stimulus frequencies, end diastolic Ca2+ levels were lower in sub-epicardial cells but higher in sub-endocardial myocytes of the heart failure group compared with controls. In general, changes were greater in heart failure animals with more severe in vivo ventricular dysfunction (ejection fraction < or = 44%).

CONCLUSIONS

Heart failure was associated with an increased cell size throughout the left ventricle, but the form of the changes in electrophysiology and Ca2+ transient were dependent on the myocyte sub-type. In particular sub-endocardial cells displayed markedly different changes compared to the other myocyte sub-types.

Expression of a single pair of desmosomal glycoproteins renders the corneal epithelium unique amongst stratified epithelia

PURPOSE

To determine desmosomal glycoprotein isoform expression in bovine corneal, limbal, and conjunctival epithelium and desmosomal profile and distribution during corneal re-epithelialization.

METHODS

Immunofluorescence (IF) for desmosomal components on cryostat sections of fresh epithelia was supported by immunoblot analysis of tissue lysates. Wounded corneas maintained in organ culture were examined by IF at times up to full re-epithelialization (96 hours).

RESULT

Immunofluorescence for desmoplakin confirmed desmosome presence throughout all three epithelia. Plakoglobin was also ubiquitous. Of the desmosomal glycoproteins, desmocollin 2 (Dsc2) and desmoglein 2 (Dsg2) were expressed throughout, but Dsc3 and Dsg3 were confined to the limbus and conjunctiva, and Dscl and Dsgl were absent. Dsc2 and Dsg2 IFs were stronger in superficial layers, but Dsc3 and Dsg3 were stronger basally, fading suprabasally. Glycoprotein expression in cornea and conjunctiva was confirmed by immunoblot analysis. No change in glycoprotein expression occurred during re-epithelialization.

CONCLUSIONS

Uniquely among stratified epithelia, cornea expresses only a single pair of desmosomal glycoproteins, Dsc2 and Dsg2. Expression of Dsc3 and Dsg3 in limbus and conjunctiva coincides with their association with cell proliferation in other epithelia, but corneal epithelial cells did not express Dsc3 or Dsg3 during re-epithelialization. Absence of Dscl and Dsgl correlates with lack of keratinization in ocular epithelia. These expression patterns may have significance for the specific properties and differentiation patterns of the epithelia. Presence of desmosomes throughout re-epithelialization raises the question of how migrating cells mutually re-position.

The vaccinia virus A27L protein is needed for the microtubule-dependent transport of intracellular mature virus particles

The vaccinia virus (VV) A27L gene encodes a 14 kDa protein that is required for the formation of intracellular enveloped virus (IEV) and, consequently, normal sized plaques. Data presented here show that A27L plays an additional role in VV assembly. When cells were infected with the VV WR32-7/Ind 14K, under conditions that repress A27L expression, transport of intracellular mature virus (IMV) from virus factories was inhibited and some IMV was found in aberrant association with virus crescents. In contrast, other VV mutants (vDeltaB5R and vDeltaF13L) that are defective in IEV formation produce IMV particles that are transported out of virus factories. This indicated a specific role for A27L in IMV transport. Induction of A27L expression at 10 h post-infection promoted the dispersal of clustered IMV particles, but only when microtubules were intact. Formation of IEV particles was also impaired when cells were infected with WR32-7/14K, a VV strain expressing a mutated form of the A27L protein; however, this mutation did not inhibit intracellular transport of IMV particles. Collectively, these data define two novel aspects of VV morphogenesis. Firstly, A27L is required for both IMV transport and the process of envelopment that leads to IEV formation. Secondly, movement of IMV particles between the virus factory and the site of IEV formation is microtubule-dependent.

Inverse relation between prostate-specific antigen and insulin-like growth factor-binding protein 3 in bone metastases and serum of patients with prostate cancer

The usual osteoblastic phenotype of metastatic prostate cancer is unexplained. Here we show that tissue and serum concentrations of prostate-specific antigen (PSA)-vary inversely with a substrate protein that binds a growth factor known to activate osteoblasts. These findings suggest that PSA may contribute to the osteoblastic phenotype, and could thus represent a new drug target devoid of antiandrogenic toxicity.

The effects of targeting the vaccinia virus B5R protein to the endoplasmic reticulum on virus morphogenesis and dissemination

The consequence of redirecting the vaccinia virus (VV) B5R protein to the endoplasmic reticulum (ER) has been investigated by the addition of an ER retrieval signal KKSL (K(2)X(2)) to the B5R C-terminus. This mutant B5R gene and a version of the gene with the inactive ER retrieval sequence KKSLAL (K(2)X(4)) were inserted into the thymidine kinase locus of a VV mutant lacking the B5R gene, vDeltaB5R. Similar levels of B5R protein were made by each virus, but the B5R-K(2)X(2) protein remained sensitive to endoglycosidase H and colocalised with protein disulphide isomerase in the ER. In contrast, the B5R-K(2)X(4) protein colocalised with 1, 4-galactosyltransferase in the trans-Golgi network. Electron microscopy revealed that even when the B5R protein was redirected to the ER, intracellular mature virus particles were wrapped by cellular membranes to form intracellular enveloped virus particles, although more incompletely wrapped particles were evident compared with wild type. These intracellular enveloped virus particles were, however, unable to efficiently induce the polymerisation of actin and the plaque size formed by vB5R-K(2)X(2) was small. Nevertheless, the amount and specific infectivity of EEV produced by vB5R-K(2)X(2) were similar to those of wild type, despite the dramatic reduction in the amount of B5R protein present in vB5R-K(2)X(2) EEV.

Calcium/calmodulin-dependent protein kinase II activity is increased in sarcoplasmic reticulum from coronary artery ligated rabbit hearts

A protein kinase activity intrinsic to the sarcoplasmic reticulum was studied in normal and hypertrophied rabbit hearts. The relationship between this kinase activity and phospholamban phosphorylation was examined. Calmodulin-dependent kinase II activity was found to be increased in sarcoplasmic reticulum preparations from hypertrophied hearts compared with normal. This was evident by measuring the phosphotransferase activity of the kinase and also by examining phospholamban phosphorylation by electrophoretic band shift analysis. Increased phospholamban phosphorylation by Calmodulin-dependent protein kinase II was dependent on prior phosphorylation by cAMP-dependent protein kinase, indicating potential crosstalk. Specific immunoblot analysis of the rabbit sarcoplasmic reticulum identified the presence of the delta form of calmodulin dependent protein kinase II and showed it to be up-regulated in hypertrophied hearts.

Immune modulation by proteins secreted from cells infected by vaccinia virus

Vaccinia virus comprises the live vaccine that was used for vaccination against smallpox. Following the eradication of smallpox, vaccinia virus was developed as an expression vector that is now used widely in biological research and vaccine development. In recent years vaccinia virus and other poxviruses have been found to express a collection of proteins that block parts of the host response to infection. Some of these proteins are secreted from the infected cell where they bind and neutralise host cytokines, chemokines and interferons (IFN). In this paper three such proteins that bind interleukin (IL)-1 beta, type I IFNs and CC chemokines are described. The study of these immunomodulatory molecules is enhancing our understanding of virus pathogenesis, yielding fundamental information about the immune system, and providing new molecules that have potential application for the treatment of immunological disorders or infectious diseases.

Effective induction of simian immunodeficiency virus-specific cytotoxic T lymphocytes in macaques by using a multiepitope gene and DNA prime-modified vaccinia virus Ankara boost vaccination regimen

DNA and modified vaccinia virus Ankara (MVA) are vaccine vehicles suitable and safe for use in humans. Here, by using a multicytotoxic T-lymphocyte (CTL) epitope gene and a DNA prime-MVA boost vaccination regimen, high levels of CTLs specific for a single simian immunodeficiency virus (SIV) gag-derived epitope were elicited in rhesus macaques. These vaccine-induced CTLs were capable of killing SIV-infected cells in vitro. Fluorescence-activated cell sorter analysis using soluble tetrameric major histocompatibility complex-peptide complexes showed that the vaccinated animals had 1 to 5% circulating CD8(+) lymphocytes specific for the vaccine epitope, frequencies comparable to those in SIV-infected monkeys. Upon intrarectal challenge with pathogenic SIVmac251, no evidence for protection was observed in at least two of the three vaccinated animals. This study does not attempt to define correlates of protective immunity nor design a protective vaccine against immunodeficiency viruses, but it demonstrates clearly that the DNA prime-MVA boost regimen is an effective protocol for induction of CTLs in macaques. It also shows that powerful tools for studying the role of CTLs in the control of SIV and human immunodeficiency virus infections are now available: epitope-based vaccines, a protocol for an effective induction of CTLs in primates, and a simple and sensitive method for quantitation of epitope-specific T cells. The advantages of the DNA prime-MVA boost regimen as well as the correlations of tetramer staining of peripheral blood lymphocytes with CTL killing in vitro and postchallenge control of viremia are discussed.

Stress-induced alterations of blood pressure and 24 h ambulatory blood pressure in adolescents

OBJECTIVE

To examine the extent to which ambulatory blood pressure was predicted by blood pressure levels exhibited during talking segments of a laboratory protocol and by resting blood pressures in male and female adolescents from three ethnic groups: African, European and Hispanic Americans.

DESIGN

This was a laboratory-field study incorporating an experimental study of reactivity of blood pressure during a laboratory protocol and an observational study of 24h ambulatory blood pressure (ABP) monitoring.

METHODS

Resting blood pressure, reactivity of blood pressure, 24h ABP, and activity, height, and maturation of a multi-ethnic sample of 373 male and female adolescents aged 11-16 years were measured. A mixed-effects model for repeated measures was the statistical approach, with systolic and diastolic blood pressures as separate, dependent variables.

RESULTS

Percentiles of ABP by sex, ethnic group, and height are presented. High and mixed blood pressure reactors in the laboratory had higher levels of 24h ABP and higher levels of blood pressure load during the daytime. African Americans had higher ABP than did European and Hispanic Americans.

CONCLUSIONS

Blood pressure measured during laboratory tasks that require talking might be useful as a screening device to identify adolescents with high blood pressures. Further study will be necessary in order to quantify the sensitivity of the laboratory protocol as an indicator of high blood pressure compared with casual measurement of blood pressures. If laboratory patterns of blood pressure could be used to predict which individuals have high levels of blood pressure during the course of daily activities, the laboratory protocol would be a useful screening tool, identifying high-risk individuals.

Cell motility and cell morphology: how some viruses take control

Viruses replicate inside host cells, where they use host biochemical and structural components to facilitate the production of new virus particles. As a consequence of co-evolution with their hosts, viruses have acquired host genes and genetic mutations that confer dominance over normal cell function. Research on virus-cell interactions has focused on the identification of mechanisms of virus dominance in order to develop therapeutic strategies for preventing productive infection. Although such research remains an essential part of molecular virology, viruses are also important genetic tools that can be used to analyse cell function. Because virus genomes contain genetic information, some of which was derived from host cells, it is possible that the analyses of virus-host interactions might lead to the identification of functionally dominant virus genes and novel eukaryotic counterparts. In this article, we have described how transforming and non-transforming viruses can control cell motility (cell migration or membrane projection), and explained how the analysis of virus cytopathic effects (CPEs) led to the identification of a novel family of cellular genes that regulate diverse aspects of cell motility.

Thermal dehydration-induced thirst in spontaneously hypertensive rats

Spontaneously hypertensive (SH) rats and normotensive Wistar-Kyoto (WKY) rats were exposed to either 25 or 37.5 degrees C for 3.5 h, and their thermal and water balance responses were compared. After exposure, either a blood sample was obtained or the rats were allowed to rehydrate for 4 h. SH rats had both higher core temperatures and evaporative water losses during heat exposure. Measurements of hematocrit, hemoglobin concentration, plasma protein and sodium concentrations, and plasma osmolality indirectly showed that the SH rats were dehydrated relative to the WKY rats after exposure to either 25 or 37.5 degrees C. SH rats drank significantly more water but also had significantly higher urine volumes than the WKY rats and thus rehydrated only slightly better than the WKY rats. SH and WKY rats had similar levels of water intake and urine output after 24 h of water deprivation. The elevated thermal response of SH rats to heat exposure does not appear to lead to uncompensatable changes in body water status.

Vaccinia virus strains Lister, USSR and Evans express soluble and cell-surface tumour necrosis factor receptors

Poxviruses encode a broad range of proteins that interfere with host immune functions such as soluble versions of cytokine receptors. Soluble virus tumour necrosis factor receptors (vTNFRs) were described originally in myxoma and Shope fibroma viruses. Cowpox virus (CPV) encodes three vTNFRs (CrmB, CrmC and CrmD). The genes equivalent to CrmB and CrmC in vaccinia virus (VV) Copenhagen are mutated and are named B28R/C22L and A53R, respectively. CrmD was identified recently in CPV and ectromelia virus but the gene is absent in VV Copenhagen. We have tested for expression of soluble binding activity for human TNF in cultures infected with 18 orthopoxviruses and have found that TNFRs are mostly absent but are produced by VV strains Lister, USSR and Evans, by the CPV elephantpox and by camelpox virus. Interestingly, we also found TNFR activity on the surface of cells infected with VV Lister, USSR and Evans. Sequence analysis of the relevant regions in VV Lister identified an intact A53R gene and an inactive B28R gene. Expression of VV Lister A53R in baculovirus and VV Western Reserve demonstrated that gene A53R encodes an active soluble vTNFR of 22 kDa. Expression and characterization of recombinant vTNFRs from VV Lister (A53R) and CPV (CrmB and CrmC) showed a similar binding specificity, with each receptor binding TNF from man, mouse and rat, but not human lymphotoxin-alpha. Lastly, the VV Lister and CPV vTNFRs bind human TNF with high affinity and prevent the binding of TNF to cellular receptors.

Interactions between vaccinia virus IEV membrane proteins and their roles in IEV assembly and actin tail formation

The intracellular enveloped form of vaccinia virus (IEV) induces the formation of actin tails that are strikingly similar to those seen in Listeria and Shigella infections. In contrast to the case for Listeria and Shigella, the vaccinia virus protein(s) responsible for directly initiating actin tail formation remains obscure. However, previous studies with recombinant vaccinia virus strains have suggested that the IEV-specific proteins A33R, A34R, A36R, B5R, and F13L play an undefined role in actin tail formation. In this study we have sought to understand how these proteins, all of which are predicted to have small cytoplasmic domains, are involved in IEV assembly and actin tail formation. Our data reveal that while deletion of A34R, B5R, or F13L resulted in a severe reduction in IEV particle assembly, IEVs formed by the DeltaB5R and DeltaF13L deletion strains, but not DeltaA34R, were still able to induce actin tails. The DeltaA36R deletion strain produced normal amounts of IEV particles, although these were unable to induce actin tails. Using several different approaches, we demonstrated that A36R is a type Ib membrane protein with a large, 195-amino-acid cytoplasmic domain exposed on the surface of IEV particles. Finally, coimmunoprecipitation experiments demonstrated that A36R interacts with A33R and A34R but not with B5R and that B5R forms a complex with A34R but not with A33R or A36R. Using extracts from DeltaA34R- and DeltaA36R-infected cells, we found that the interaction of A36R with A33R and that of A34R with B5R are independent of A34R and A36R, respectively. We conclude from our observations that multiple interactions between IEV membrane proteins exist which have important implications for IEV assembly and actin tail formation. Furthermore, these data suggest that while A34R is involved in IEV assembly and organization, A36R is critical for actin tail formation.

Ty virus-like particles, DNA vaccines and Modified Vaccinia Virus Ankara; comparisons and combinations

Three types of vaccine, all expressing the same antigen from Plasmodium berghei, or a CD8+ T cell epitope from that antigen, were compared for their ability to induce CD8+ T cell responses in mice. Higher levels of lysis and numbers of IFN-gamma secreting T cells were primed with Ty virus-like particles and Modified Vaccinia Virus Ankara (MVA) than with DNA vaccines, but none of the vaccines were able to protect immunised mice from infectious challenge even after repeated doses. However, when the immune response was primed with one type of vaccine (Ty-VLPs or DNA) and boosted with another (MVA) complete protection against infection was achieved. Protection correlated with very high levels of IFN-gamma secreting T cells and lysis. This method of vaccination uses delivery systems and routes that can be used in humans and could provide a generally applicable regime for the induction of high levels of CD8+ T cells.

Nuclear and nucleolar localization of an African swine fever virus protein, I14L, that is similar to the herpes simplex virus-encoded virulence factor ICP34.5

PCR analysis of the genomes of 18 different African swine fever virus (ASFV) isolates showed that the I14L open reading frame (ORF) was present as either a long form or short form in all of the isolates. Sequencing of the ORF from eight isolates confirmed that both forms of the ORF were well conserved. Antisera raised against the I14L protein identified the long form of the protein as a 21 kDa protein expressed late during ASFV infection. Immunofluorescent analysis of transiently expressed haemagglutinin-tagged forms of the I14L protein showed that the long form of the protein localized predominantly to the nucleus and within the nucleoli. In contrast, although the short form of the protein was also present predominantly in the nucleus, it did not localize to the nucleoli. Deletion of the N-terminal 14 amino acids from the long form of the I14L protein, which includes a high proportion of basic Arg/Lys residues, abolished the specific nucleolar localization of the protein, although the protein was still present in the nucleus. Addition of this 14 amino acid sequence to beta-galactosidase or replacement of the N-terminal 14 amino acids of the I14L short form with those from the long form directed both of these modified proteins to the nucleolus. This indicates that this 14 amino acid sequence contains all the signals required for nucleolar localization.

An exploration of varieties of visual attention: ERP findings

A set of five tasks was designed to examine dynamic aspects of visual attention: selective attention to color, selective attention to pattern, dividing and switching attention between color and pattern, and selective attention to pattern with changing target. These varieties of visual attention were examined using the same set of stimuli under different instruction sets; thus differences between tasks cannot be attributed to differences in the perceptual features of the stimuli. ERP data are presented for each of these tasks. A within-task analysis of different stimulus types varying in similarity to the attended target feature revealed that an early frontal selection positivity (FSP) was evident in selective attention tasks, regardless of whether color was the attended feature. The scalp distribution of a later posterior selection negativity (SN) was affected by whether the attended feature was color or pattern. The SN was largely unaffected by dividing attention across color and pattern. A large widespread positivity was evident in most conditions, consisting of at least three subcomponents which were differentially affected by the attention conditions. These findings are discussed in relation to prior research and the time course of visual attention processes in the brain.

Effective induction of HIV-specific CTL by multi-epitope using gene gun in a combined vaccination regime

Reliable and effective induction of cytotoxic T-lymphocytes (CTL) is one of the prime objectives of vaccine research. Previously, novel HIV vaccine candidates were constructed as a string of CTL epitopes (20 human, 3 macaque and 1 mouse) delivered using a DNA vector [Hanke T, Schneider J, Gilbert SG, Hill AVS, McMichael A. DNA multi-CTL epitope vaccines for HIV and Plasmodium falciparum: immunogenicity in mice. Vaccine 1998;16:426-435.] or modified vaccinia Ankara (MVA [Hanke T, Blanchard TJ, Schneider J, Ogg GS, Tan R, Becker MSC, Gilbert SG, Hill AVS, Smith GL, McMichael A. Immunogenicities of intravenous and intramuscular administrations of MVA-based multi-CTL epitope vaccine for HIV in mice. J Gen Virol 1998;79:83-90.]), i.e. vaccine vehicles acceptable for use in humans. In mice, a single intramuscular (i.m.) needle injection of either vaccine alone elicited good CTL responses. Here, it is demonstrated that the multi-epitope DNA also induced CTL when delivered intradermally using the Accell gene gun. The CTL responses increased after re-immunization and after three deliveries were comparable to those induced by a single i.m. injection. Recent evidence indicates that combining routes and vaccine vehicles enhances the immunogenicity of vaccine-delivered or -encoded antigens. Here, it is shown that administration of DNA by an i.m. priming/gene gun boosting more efficiently induced CTL than gene gun priming/i.m. boosting. A similar increment was obtained by sequential vaccinations using a gene gun-delivered DNA followed by recombinant MVA. Thus particular sequences of routes or vaccine vehicles rather than simple prime-boost delivery of a single vaccine is critical for an effective elicitation of CTL.

Vaccinia virus intracellular mature virions contain only one lipid membrane

Vaccinia virus (VV) morphogenesis commences with the formation of lipid crescents that grow into spherical immature virus (IV) and then infectious intracellular mature virus (IMV) particles. Early studies proposed that the lipid crescents were synthesized de novo and matured into IMV particles that contained a single lipid bilayer (S. Dales and E. H. Mosbach, Virology 35:564-583, 1968), but a more recent study reported that the lipid crescent was derived from membranes of the intermediate compartment (IC) and contained a double lipid bilayer (B. Sodiek et al., J. Cell Biol. 121:521-541, 1993). In the present study, we used high-resolution electron microscopy to reinvestigate the structures of the lipid crescents, IV, and IMV particles in order to determine if they contain one or two membranes. Examination of thin sections of Epon-embedded, VV-infected cells by use of a high-angular-tilt series of single sections, serial-section analysis, and high-resolution digital-image analysis detected only a single, 5-nm-thick lipid bilayer in virus crescents, IV, and IMV particles that is covered by a 8-nm-thick protein coat. In contrast, it was possible to discern tightly apposed cellular membranes, each 5 nm thick, in junctions between cells and in the myelin sheath of Schwann cells around neurons. Serial-section analysis and angular tilt analysis of sections detected no continuity between virus lipid crescents or IV particles and cellular membrane cisternae. Moreover, crescents were found to form at sites remote from IC membranes-namely, within the center of virus factories and within the nucleus-demonstrating that crescent formation can occur independently of IC membranes. These data leave unexplained the mechanism of single-membrane formation, but they have important implications with regard to the mechanism of entry of IMV and extracellular enveloped virus into cells; topologically, a one-to-one membrane fusion suffices for delivery of the IMV core into the cytoplasm. Consistent with this, we have demonstrated previously by confocal microscopy that uncoated virus cores within the cytoplasm lack the IMV surface protein D8L, and we show here that intracellular cores lack the surface protein coat and lipid membrane.

Enhanced phosphorylation of phospholamban and downregulation of sarco/endoplasmic reticulum Ca2+ ATPase type 2 (SERCA 2) in cardiac sarcoplasmic reticulum from rabbits with heart failure

OBJECTIVES

To assess the phosphorylation of myocardial phospholamban (PLB) and quantify protein levels of PLB and sarco/endoplasmic reticulum Ca2+ ATPase type 2 (SERCA 2) in a rabbit model of heart failure. Furthermore, to correlate these parameters with the rate of Ca2+ uptake into sarcoplasmic reticulum (SR) vesicles.

METHODS

Heart failure in the rabbit was indicated by the pronounced ventricular contractile dysfunction accompanied by post-mortem evidence of lung and liver congestion 8 weeks after a coronary artery ligation procedure. Phosphorylation of PLB was measured by reduced mobility of the phosphorylated forms on Tris-glycine gels. Phosphoserine and phosphothreonine-specific antibodies against PLB were used to determine the phosphorylated residues. Immunoblotting combined with densitometry was used to assess PLB and SERCA 2 levels. Finally, oxalate-supported Ca2+ uptake into SR vesicles was studied using the fluorescent indicator Fura-2.

RESULTS

The phosphorylation state of PLB was significantly higher in myocardium isolated from left ventricles of heart failure rabbits (8.3 +/- 0.42 P-PLB) when compared with sham-operated animals (4.0 +/- 1.7 P-PLB). The kinase activity associated with SR vesicles isolated from animals with heart failure was a factor of 1.58 +/- 0.21-times higher than sham hearts, as assessed by the initial rate of phosphorylation of PLB. This higher kinase activity observed in heart failure was not completely abolished by inhibitors of either A-kinase, C-kinase or Ca2+/calmodulin-dependent protein kinase (CaM-kinase). Abundance of SERCA in heart failure myocardial homogenates was significantly less than sham values (0.68 +/- 0.11 vs. 1.74 +/- 0.27) as was PLB (0.41 +/- 0.08 vs. 0.69 +/- 0.13), similar reductions were seen in vesicle preparations. The rate constant of Ca2+ uptake into the isolated SR vesicles was lower in preparations from heart failure myocardium than from sham myocardium (2.50 +/- 0.23 ms vs. 4.43 +/- 0.3 ms).

CONCLUSIONS

The higher level of phosphorylation of PLB observed in the left ventricle of rabbits with heart failure is associated with a higher intrinsic kinase activity of the SR. However, the abundance of both of SERCA 2 and PLB proteins are lower in heart failure. The net effect of these changes appears to be a reduced rate of Ca2+ uptake by the SR in heart failure.

Using confocal microscopy to study virus binding and entry into cells

The chapter presents a discussion on the study of virus binding and entry into cells by using confocal microscopy. For the study new approaches to study vaccinia virus (VV), binding and entry based on confocal microscopy are developed. These techniques do not require virus purification or labeling and generate data that reveal the absolute numbers of virus particles that have bound to or have entered into individual cells. The chapter describes these techniques and then illustrates with some of the results obtained. These methods should be applicable to any virus larger than 50 nm. The chapter discusses the way these techniques have generated data that cannot be obtained with classical binding or entry assays. Vaccina virus is the prototype of the poxvirus family. These are DNA viruses that replicate in the cell cytoplasm and have genomes between 150 and 300 kbp. These techniques are presented with a study of the binding and entry of VV. The methods have been particularly useful for studying VV because this virus produces two different forms of infectious virion that are antigenically and biologically distinct and are produced in widely differing amounts. Moreover, the extracellular enveloped virus (EEV) form of VV cannot be purified from contaminating IMV without disrupting the integrity of the outer envelope.

Vaccinia virus immune evasion

Vaccinia virus expresses many virulence factors that are non-essential for virus replication in cell culture but are important in vivo. In this paper three mechanisms are described that are used by vaccinia virus to evade the host immune response to infection. One of these is the release of a soluble protein that binds CC chemokines and that is unrelated to cellular chemokine receptors. The other two mechanisms are displayed by virus particles that are released from infected cells. This form of vaccinia virus is called extracellular enveloped virus (EEV) and is resistant to neutralisation by antibody and to destruction by complement. Resistance to complement is mediated by the acquisition of host complement control proteins, particularly CD55, during virus release from infected cells.