Impact of HEART Score Decision Aid on Coronary Computed Tomography Angiography Utilization and Diagnostic Yield in the Emergency Department

OBJECTIVE

Emergency physicians are challenged to efficiently and reliably risk stratify patients presenting with chest pain (CP) to optimize diagnostic testing and avoid unnecessary hospital admissions. The objective of our study was to evaluate the impact of a HEART score-based decision aid (HSDA) integrated in the electronic health record on coronary computed tomography angiography (CCTA) utilization and diagnostic yield in adult emergency department (ED) CP patients with suspected acute coronary syndrome.

METHODS

We conducted a before and after study to determine whether implementation of a mandatory computerized HSDA would reduce CCTA utilization in ED CP patients and improve the diagnostic yield of obstructive coronary artery disease (CAD) (≥50%). We included all adult ED CP patients with suspected acute coronary syndrome during the first 6 months of 2018 (before) and 2020 (after) at a large academic center. CCTA utilization and obstructive CAD yield were compared in patients before and after implementing the HSDA using χ2 tests. Secondarily, we assessed the association of HEART scores and CCTA results.

RESULTS

Of the 3095 CP patients during the before study period, 733 underwent CCTA. Of the 2692 CP patients during the after study period, 339 underwent CCTA. CCTA utilization before and after HSDA was 23.4% [95% confidence interval (95% CI), 22.2-25.2] and 12.6% (95% CI, 11.4-13.0), respectively; mean difference was 11.1% (95% CI, 0.9-13.0). Among 1072 patients undergoing CCTA, mean (SD) age and percent females before versus after HSDA were 54 (11) versus 56 (11) years and 50% versus 49%, respectively. We included 1014 patients (686 before and 328 after) for the yield analysis. Obstructive CAD was present in 15% (95% CI, 12.7-17.9) and 20.1% (95% CI, 16.1-24.7) before and after HSDA, respectively; mean difference was 4.9% (95% CI, 0.1-10.1).

CONCLUSIONS

Implementation of a mandatory electronic health record HSDA aid reduced ED CCTA utilization by half and improved the diagnostic yield.

The Negro River (Ancash-Peru): A unique case of water pollution, three environmental scenarios and an unresolved issue

This paper is focused on the hydrogeochemical characterization of the Negro River along its course, as well as in the proposal of a functioning model for the contamination processes in order to establish potential cause-effect relationships between water quality, geology (ARD), mining activities (AMD) and the tectonic framework as transmission vector of acidity, metals and sulphates. The scenario shows a heavily-contaminated river compared to the unaffected regional background. By graphical and statistical treatments of physico-chemical data of Negro River and the unaffected values of regional background and other AMD/ARD representative rivers' it is possible to conclude that Antamina Mine, is not the cause of the Negro River contamination, without the need of isotopic tracers, but just through the inexistent concentrations of Cu, Bi and Mo found in the waters. In the proposed contamination model, climatic factors (glacial retreat) activate geological (ARD) processes. The tectonic scenario (faults) intervenes as a transport medium of the contamination flux from the sulphide oxidation surface in upper altitudes until the spring in lower altitudes. At the end, it is concluded that this contamination comes from the recent glacial retreat in areas near the Cordillera Blanca that has left massive amounts of sulphide materials exposed to weathering conditions, oxidizing naturally (ARD processes) and finally contributing to the contamination of the Negro River through faults. In this case, we would face an ARD process in the strict sense, which is the direct oxidation of sulphides outcropping in the upper part of the mountain with the generation of sulphates, the release of hydrogen ions and the consequent generation of acid and the dissolution of the metals. This ARD process would come from the glacial retreat, which, through the faults, transports contaminated water until the spring.

Processing of mycotoxin contaminated waste streams through anaerobic digestion

Food and feed stocks heavily contaminated with mycotoxins are rendered unfit for consumption and therefore discarded as waste. Due to the lack of guidelines and in accordance with the prudent avoidance principle, these waste streams are often incinerated. For better valorization, these streams could be used as input for anaerobic digestion. However, the degradation of multiple mycotoxins during anaerobic digestion and their effect on the methane production is currently unknown. In batch tests spiked with mycotoxins, aflatoxin B1, ochratoxin A, deoxynivalenol, zearalenone and T-2 toxin were degraded for more than 90%. For mesophile and thermophile digestion respectively, fumonisin B1 was degraded for 70% and 85%, and most ergot alkaloids for 64% and 98%. Neither biogas production, nor methane production were influenced by the presence of the mycotoxins. Subsequently, semi-continuous reactors fed with contaminated maize resulted in more than 99% degradation for all mycotoxins after 1.8 hydraulic retention time with stable biogas production and process parameters. This study shows that mycotoxin contaminated organic waste can be safely valorized to methane while the digestate is void of mycotoxin residues.

Usefulness of a novel Caco-2 cell perfusion system II. Characterization of monolayer properties and peptidase activity

In this study, the enzymatic activity and the influence of support filters and extracellular matrix proteins on the differentiation of Caco-2 cells grown in a perfusion system (Minucells and MinutissueTM) were examined and compared to traditional culturing approaches. Differences were observed regarding the differentiation of Caco-2 cells using the traditional approach and perfusion system such that the cell monolayers grown in a perfusion system showed a significant increase in dipeptidase activities (18.20 +/- 0.43nmol x min(-1) x cm(-2)) compared to the cells cultivated using the 21-day protocol (9.45 +/- 0.50 nmol x min(-1) x cm(-2)). The peptidase activity of Caco-2 cells was strikingly inhibited when Matrigel extracellular protein was used for coating polycarbonate support filters. While the enzymatic activities of the cell monolayers differentiated in the perfusion system were up-regulated, the transepithelial electrical resistance values of the cell monolayers (171 +/- 52 and 251 +/- 62 omega x cm2 for polycarbonate and polyester, respectively) decreased compared to the traditional Snapwell inserts (644 +/- 119 omega x cm2). The results suggested that the perfusion systems were useful permeability models which reduce workload, resources and manpower needed to obtain useful Caco-2 monolayers. In addition, the approach offers an efficient tool for long-term culturing of highly differentiated Caco-2 cell monolayers.

Parallel artificial membrane permeability assay (PAMPA) combined with a 10-day multiscreen Caco-2 cell culture as a tool for assessing new drug candidates

The parallel artificial membrane permeability assay (PAMPA) is extensively used for the evaluation of early drug candidates. It is high throughput, low cost and is amenable to automation. This method has been shown useful in assessing transmembrane, non-energy dependent, diffusion of drugs such that reasonable predictability with in vivo (passive) absorption is possible. Cell cultures mimicking the gastrointestinal tract such as the CACO-2 cultures have the advantage of taking into account other transport mechanism including paracellular and carrier-mediated uptake but are lower throughput and labor-intensive. In this study, the applicability of two high throughput permeability assays namely PAMPA (PSR4p, pION Inc.) and 96-well Caco-2 cell assay (MultiScreen, Millipore) were used to rank drug permeability as well as to predict passive and active drug absorption/secretion for a series of marketed drugs as well as a collection of structurally diverse drug candidates. CACO-2 cells were cultured using MultiScreen hardware over a period of 10 days with the integrity of the cells assessed using transepithelial electrical resistance (TEER) and by the ability of the monolayer to the transport a paracellular marker, sodium fluorescence. Effective permeability (Peff) data were calculated using spectrophotometric data and were binned based on a pre-defined cut-off values as either highly and poorly permeable. A comparison of a well characterized drug training set indicate at least 85% concordance between the data generated from PAMPA and Caco-2 MultiScreen. The values obtained using the MultiScreen approach were also similar to data obtained from the literature using the conventional 21-day Caco-2 cell assay. Differences between PAMPA and CACO-2 ranking were useful indicators of either drug efflux (PAMPA (Peff) > CACO-2 (Peff)) or absorptive transport (CACO-2 (Peff) > PAMPA (Peff)). These results indicate that PAMPA combined with the MultiScreen Caco-2 cell culture may be a useful high throughput screening for predicting passive diffusion and active transport of new drugs.

Probing white dwarf interiors with LISA: periastron precession in eccentric double white dwarfs

In globular clusters, dynamical interactions give rise to a population of eccentric double white dwarfs detectable by the Laser Interferometer Space Antenna (LISA) up to the Large Magellanic Cloud. In this Letter, we explore the detectability of periastron precession in these systems with LISA. Unlike previous investigations, we consider contributions due to tidal and rotational distortions of the binary components in addition to general relativistic contributions to the periastron precession. At orbital frequencies above a few mHz, we find that tides and stellar rotation dominate, opening up a possibly unique window to the study of the interior and structure of white dwarfs.

Inhibition of TNF-alpha production by pentoxifylline does not prevent endotoxin-induced decrease in serum IGF-I

Sepsis and endotoxin (LPS or lipopolysaccharide) injection induce a state of growth hormone (GH) resistance leading to decreased circulating insulin-like growth factor (IGF)-I. Because the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta inhibit the GH-stimulated IGF-I expression in vitro, it was tempting to speculate that these two cytokines might play an important role in the reduction of circulating IGF-I levels caused by LPS. Pentoxifylline, a methylxanthine usually used in the treatment of peripheral arterial circulatory disorders, has been reported to inhibit TNF-alpha synthesis. The goal of our study was to investigate whether inhibition of TNF-alpha production by pentoxifylline could prevent the decrease in IGF-I and the GH resistance caused by LPS injection. Because previous studies demonstrated that pentoxifylline can reduce muscle catabolism induced by sepsis, we also assessed whether pentoxifylline could exert its anticatabolic effect by preventing the decrease in circulating IGF-I. LPS injection in rats decreased serum IGF-I (-45% at 12 h; P<0.01 vs time 0) and its liver mRNA (-67% at 12 h; P<0.01 vs time 0) while it induced circulating TNF-alpha and IL-1beta and their hepatic expression (P<0.01). Pretreatment of LPS-treated animals by pentoxifylline abolished the LPS-induced rise in serum TNF-alpha (-98% at 90 min; P<0.001 vs LPS alone) and to a lesser extent in serum IL-1beta (-44% at 3 h; not significant vs LPS alone). Despite its dramatic inhibitory effect on TNF-alpha induction, however, pentoxifylline failed to suppress both the decrease in IGF-I and the GH resistance induced by LPS in rats. These results suggest that mediators other than TNF-alpha, in particular IL-1beta or IL-6, could contribute to the GH resistance induced by LPS. They also suggest that the anticatabolic effect of pentoxifylline is not due to prevention of the decline of circulating IGF-I.

Matching multicomponent objects from different viewpoints: mental rotation as normalization?

Novel multicomponent objects were created, and 3 distractors were created for each object by changing the relations between the parts of the object. In a set of 5 experiments, target objects were presented as a motion sequence of multiple views or as a single view. Participants were asked to determine whether an image of an object, viewed from another viewpoint, was the same as the target object. The axis of rotation was aligned with one of the environmental axes or with the main axis of the object. The effects of viewpoint on performance imply that the matching of objects is viewpoint dependent and requires a process of normalization to undo the differences between the perceptual description and the stored object descriptions. The lack of a systematic effect of the axis of rotation, however, suggests that this normalization is best understood as not involving a 3-D transformation of stored 3-D object models.

Multiple routes to object matching from different viewpoints: mental rotation versus invariant features

Previous research has shown that object recognition from different viewpoints often yields strong effects of viewpoint. However, for some objects and experimental paradigms almost complete viewpoint invariance is obtained. This suggests the existence of multiple routes to object recognition. In this study we further strengthen this notion by designing two different conditions using the same experimental paradigm (simultaneous matching) and highly similar objects (multiblock figures). In the first condition (involving a handedness violation), strong effects of viewpoint were obtained. In the second condition (involving an invariance violation), the effects of viewpoint were negligible. This result illustrates that asking under what circumstances object recognition is viewpoint dependent or independent is more fruitful than attempting to show that object recognition is either viewpoint dependent or independent.

The urge to smoke depends on the expectation of smoking

AIMS

An earlier study (Dols et al. 2000) suggested that cue-induced urge to smoke depends on the expectation of smoking. The present study tried to replicate the findings under stringently controlled conditions.

DESIGN

A 2 (context) x 2 (cues) x 6 (trial) within-subject design. Each smoker entered two different contexts; one context predicted the future occurrence of smoking (i.e. one puff of a cigarette) and one context predicted the non-occurrence of smoking. In each context smokers were exposed to smoking cues (i.e. cigarettes and lighter) or not.

SETTING

Laboratory at Maastricht University.

PARTICIPANTS

Thirty-two daily smokers, smoking at least five cigarettes a day for at least 2 years.

MEASUREMENTS

Participants reported their urge to smoke in each context in the presence and absence of smoking cues using a computerized visual analogue scale (VAS).

FINDINGS

The results revealed that the urge to smoke was higher in a context in which smoking was expected relative to a context in which it was not expected. As in the previous study the urge-inducing effect of smoking cues was larger in the smoking context than in the non-smoking context. Moreover, smoking cues did not have a significant effect in the non-smoking context.

CONCLUSIONS

It was shown that smoking cues elicit craving due mainly to a generated expectation of the occurrence of smoking and less due to salience or long history of associative learning. Theoretical and practical implications of the results are discussed.

Genetic variability of the V1 and V2 env domains of SIVcpz-ant and neutralization pattern of plasma viruses in a chimpanzee infected naturally

Specific neutralizing epitope changes have been observed in a chimpanzee infected naturally with SIVcpz, which differ from HIV-1 infecting humans. To characterize further these changes, a longitudinal study of env genomic sequence variation of SIVcpz-ant isolates was undertaken in this animal. The V1 and V2 regions of the env were determined to arise from specific recombination events. To determine whether recombination of the V1 and V2 domains was possibly associated with the emergence of neutralization escape viruses, envelope sequences and gene length polymorphisms from PBMC and plasma viral variants were studied over a 7-year period. PBMCs and plasma-associated infectious virus titers as well as plasma RNA viral loads were monitored longitudinally. The first 5 viruses isolated from the plasma were found to be neutralization escape variants. Sequence analysis of their V1 and the V2 regions indicated that a 20 amino acid stretch of the V1 region had undergone recombination and was also associated with the emergence of isolates eliciting strong neutralization responses. These findings support the hypothesis that recombination of the V1 and V2 regions of the envelope play a role in neutralization escape of SIVcpz in chimpanzees infected naturally. Furthermore, the data confirm that the neutralizing antibody response plays an important role in the decline of plasma infectious virus titers in HIV-1 related SIVcpz nonpathogenic infection.

Longitudinal comparison of virus load parameters and CD8 T-cell suppressive capacity in two SIVcpz-infected chimpanzees

In a longitudinal study we address the hypothesis that resis tance to disease progression in lentivirus-infected chimpanzees is related to potent non-cytotoxic suppression of virus replication. In a long-term follow-up, the viral suppressive capacity in two simian immunodeficiency virus (SIV)cpz-infected chimpanzees was correlated with two polymerase chain reaction (PCR)- and two culture-based virus load measurements. In both animals, quantitative virus isolation (QVI) tended to decline slowly, whereas in vitro virus suppression was sustained or increased over time. In general, plasma virus loads in SIVcpz-infected animals were maintained for extended periods of time. Based on current assays that measure virus suppressive capacity in peripheral blood, it was not possible to conclude that virus suppression played a major role in the maintenance of the disease-free state in lentivirus-infected chimpanzees.

Matching multicomponent objects from different viewpoints: mental rotation as normalization?

Novel multicomponent objects were created, and 3 distractors were created for each object by changing the relations between the parts of the object. In a set of 5 experiments, target objects were presented as a motion sequence of multiple views or as a single view. Participants were asked to determine whether an image of an object, viewed from another viewpoint, was the same as the target object. The axis of rotation was aligned with one of the environmental axes or with the main axis of the object. The effects of viewpoint on performance imply that the matching of objects is viewpoint dependent and requires a process of normalization to undo the differences between the perceptual description and the stored object descriptions. The lack of a systematic effect of the axis of rotation, however, suggests that this normalization is best understood as not involving a 3-D transformation of stored 3-D object models.

Visual determinants of reduced performance on the Stroop color-word test in normal aging individuals

It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop performance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated with more time needed on card I (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with slower performance on card 3 (interference). Half of the age-related variance in speed performance was shared with visual function. The actual impact of reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual function decrements. It is suggested that reduced visual function has differential effects on Stroop performance which need to be accounted for when the Stroop test is used both in research and in clinical settings. Stroop performance measured from older individuals with unknown visual status should be interpreted with caution.

The influence of two-dimensional stimulus properties in a reconstruction task with minimal information stimuli

Effects of viewpoint that are typically found in shape recognition tasks have been interpreted in the past as strong evidence against approaches based on the use of geometric invariants by the human visual system. At first sight, the use of such invariants would indeed predict shape recognition to be viewpoint independent. It has been argued before, however, that the visual estimation of invariants need not itself be invariant. Changes of viewpoint introduce changes in 2D stimulus features. The latter may make the estimation of invariants by the visual system more or less difficult. The present study explores how such 2D features influence estimation distributions in a reconstruction paradigm. Subjects were shown four coplanar dots. They were asked to estimate the position of one of the dots relative to the three others on the basis of a slanted version of the configuration. An estimation distribution was obtained for every position of the dot to be estimated. Biases in these distributions indicated that subjects performed the task by using 2D reference axes that were unambiguously identifiable in both the images of the dot pattern.

The role of the centre of projection in the estimation of slant from texture of planar surfaces

Displays were presented consisting of a perspective projection of a regular square grid, made up of vertical and horizontal equally spaced white lines, that was slanted in depth. The surface was viewed monocularly, through a circular aperture. A range of slants was shown (0 degree, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, or 60 degrees) and the observers' task was to match the slant by means of a mouse-driven probe. The viewing distance (50, 75, or 100 cm) as well as the focal distance (25, 50, 75, 100, or 125 cm) were varied. We expected the estimation error to be smallest when the viewing distance and the focal distance coincided. This was not the case. Instead, subjects seemed to use the perspective deformation of the texture elements in the stimulus display to make a slant estimation, regardless of the specific combination of viewing distance and focal distance.

Transjugular intrahepatic portosystemic shunt (TIPS) versus endoscopic variceal ligation in the prevention of variceal rebleeding in patients with cirrhosis: a randomised trial

BACKGROUND AND AIMS

The transjugular intrahepatic portosystemic shunt (TIPS) is a new therapeutic modality for variceal bleeding. In this study we compared the two year survival and rebleeding rates in cirrhotic patients treated by either variceal band ligation or TIPS for variceal bleeding.

METHODS

Eighty cirrhotic patients (Pugh score 7-12) with variceal bleeding were randomly allocated to TIPS (n=41) or ligation (n=39), 24 hours after control of bleeding.

RESULTS

Mean follow up was 581 days in the ligation group and 678 days in the TIPS group. The two year survival rate was 57% in the TIPS group and 56% in the ligation group (NS); the incidence of variceal rebleeding after two years was 18% in the TIPS group and 66% in the ligation group (p<0.001). Uncontrolled rebleeding occurred in 11 patients in the ligation group (eight were rescued by emergency TIPS) but in none of the TIPS group. The incidence of encephalopathy at two years was 47% in the TIPS group and 44% in the ligation group (NS).

CONCLUSIONS

TIPS did not increase the two year survival rate compared with variceal band ligation after variceal bleeding in cirrhotic patients with moderate or severe liver failure. It significantly reduced the incidence of variceal rebleeding without increasing the rate of encephalopathy.

The viewpoint-dependency of veridicality: psychophysics and modelling

Human observers were shown projected angles, embedded in solid cross-like figures and were asked whether these projected angles could be the projection of an orthogonal angle in 3-D space (i.e. whether the two legs of the cross were orthogonal to each other). We found that performance depended on the viewpoint at which the angle was viewed: Both slant (i.e. the angle between the normal of the target angle relative to the plane of projection) and roll (i.e. the rotation around the normal of the target angle) had a systematic effect on the proportion of errors when observers were shown non-orthogonal angles. With orthogonal angles, however, this effect was absent (i.e. very low error rate with no systematic effect of slant and roll). Instead of assuming a viewpoint-dependent bias towards orthogonality, a computational analysis of the task, using a Bayesian approach, and a computer simulation showed that the viewpoint-dependency can be modelled by a fixed set of biases in order to constrain the set of possible scenes that could give rise to the projection.

Modeling HIV transfer between dendritic cells and T cells: importance of HIV phenotype, dendritic cell-T cell contact and T-cell activation

OBJECTIVE

To study the requirements for HIV transfer between dendritic cells (DC) and CD4 T cells, using an in vitro model, combined with flow cytometry.

METHODS

Immature DC and macrophages (MA) were generated from monocytes. After infection, DC or MA were cultured alone or with purified CD4 T cells. Intracellular HIV was measured, using (1) the monocyte (MO)-tropic AD8 HIV, endowed with enhanced green fluorescent protein (EGFP); and (2) intracellular staining of laboratory HIV strains and clones from primary isolates.

RESULTS

(1) Clone AD8-EGFP infected DC and MA with equal efficiency, but the virus was preferentially transferred from DC to autologous T cells. (2) DC were more productively infected with R5/NSI, as compared to X4/SI, HIV, but both HIV phenotypes were easily transmitted to autologous T4 cells. (3) HIV-infected DC transferred the virus to T cells across a semi-permeable membrane, if the T cells were in contact with non-infected DC. (4) Co-culture of T cells with autologous non-infected DC induced T-cell activation. HIV-infected DC selectively increased HLA-DR on T cells and HLA-DR (+) T cells were preferential targets for HIV transfer. (5) Resting Ba-L-infected CD4 T cells were able to transmit the virus 'inversely' to co-cultured DC.

CONCLUSION

HIV transfer between monocyte-derived dendritic cells and autologous CD4 T cells was directly demonstrated using flow cytometry. The transfer proceeded in both directions, depended on cellular contact and was associated with partial T-cell activation. This model, representing relevant in vivo targets of HIV, is useful to further investigate interactions between HIV, DC and T cells, without the need for primary ex vivo DC.

Identification and characterization of sera from HIV-infected individuals with broad cross-neutralizing activity against group M (env clade A-H) and group O primary HIV-1 isolates

A previous study on cross-clade neutralization activity, identified three key isolates, MNlab (envB/gagB; X4 coreceptor), VI525 (envG/gagH, envA/gagA; R5X4) and CA9 (Group O; R5), that allowed discrimination of sera, likely or unlikely to neutralize primary HIV-1 isolates belonging to Group M (env clades A-H) and Group O. The prognostic ability of these three isolates was verified by means of an external validation on a different and larger set of sera. A total of 79 different sera (66 HIV-1, 10 HIV-2, 1 HIV-1+2 and 2 SIV(cpz)) were examined first for their capacity to neutralize the three key isolates, next sera were challenged against 12 other primary HIV-1 isolates of Group M (env A-H) and 2 isolates of Group O. Sera that neutralized all three isolates with an ID(50) titer of > or =1/40, also neutralized the 14 other primary isolates belonging to different genetic groups and clades. Sera that did not neutralize all three isolates did not exert broad cross-neutralizing activity. The neutralizing activity was antibody-mediated because it was absorbed and eluted from a Prot-G column. Competition-neutralization experiments using recombinant gp120 (HIV-1 MNlab) reduced the neutralizing capacity, suggesting that the neutralizing antibodies were directed against the Env protein. Remarkably, the broad cross-neutralization activity was found primarily in African female patients. In conclusion, this study confirms that three isolates are sufficient to allow identification of broad cross-neutralizing sera.

A case of giant cell hepatitis recurring after liver transplantation and treated with ribavirin

A patient who underwent orthotopic liver transplantation for giant cell hepatitis with cirrhosis and in whom giant cell hepatitis recurred twice after orthotopic liver transplantation is reported. He was treated with ribavirin with an excellent result. The literature on this subject is reviewed. This observation clearly confirms the efficacy of ribavirin for the treatment of giant cell hepatitis, thus providing evidence for its viral origin.

Lamivudine and alpha interferon combination treatment of patients with chronic hepatitis B infection: a randomised trial

BACKGROUND, AIM, AND METHODS: Alpha interferon is the generally approved therapy for HBe antigen positive patients with chronic hepatitis B, but its efficacy is limited. Lamivudine is a new oral nucleoside analogue which potently inhibits hepatitis B virus (HBV) DNA replication. To investigate the possibility of an additive effect of interferon-lamivudine combination therapy compared with interferon or lamivudine monotherapy, we conducted a randomised controlled trial in 230 predominantly Caucasian patients with hepatitis B e antigen (HBeAg) and HBV DNA positive chronic hepatitis B. Previously untreated patients were randomised to receive: combination therapy of lamivudine 100 mg daily with alpha interferon 10 million units three times weekly for 16 weeks after pretreatment with lamivudine for eight weeks (n=75); alpha interferon 10 million units three times weekly for 16 weeks (n=69); or lamivudine 100 mg daily for 52 weeks (n=82). The primary efficacy end point was the HBeAg seroconversion rate at week 52 (loss of HBeAg, development of antibodies to HBeAg and undetectable HBV DNA).

RESULTS

The HBeAg seroconversion rate at week 52 was 29% for the combination therapy, 19% for interferon monotherapy, and 18% for lamivudine monotherapy (p=0.12 and p=0.10, respectively, for comparison of the combination therapy with interferon or lamivudine monotherapy). The HBeAg seroconversion rates at week 52 for the combination therapy and lamivudine monotherapy were significantly different in the per protocol analysis (36% (20/56) v 19% (13/70), respectively; p=0.02). The effect of combining lamivudine and interferon appeared to be most useful in patients with moderately elevated alanine aminotransferase levels at baseline. Adverse events with the combination therapy were similar to interferon monotherapy; patients receiving lamivudine monotherapy had significantly fewer adverse events.

CONCLUSIONS

HBeAg seroconversion rates at one year were similar for lamivudine monotherapy (52 weeks) and standard alpha interferon therapy (16 weeks). The combination of lamivudine and interferon appeared to increase the HBeAg seroconversion rate, particularly in patients with moderately elevated baseline aminotransferase levels. The potential benefit of combining lamivudine and interferon should be investigated further in studies with different regimens of combination therapy.

The HIV-2 genotype and the HIV-1 syncytium-inducing phenotype are associated with a lower virus replication in dendritic cells

During sexual transmission, HIV infects the mucosal dendritic cells and is transferred to CD4 T cells. Whether HIV variants of a particular genetic (sub)type or phenotype selectively infect dendritic cells (DC) or are preferentially transferred to T cells remains highly controversial. To avoid the cumbersome use of primary dendritic cells, in vitro dendritic cell models were generated from precursors, either hematopoietic progenitor cells (HPC) or monocytes (MO). Productive infection in the dendritic cells and transfer of the virus to T cells was assessed for a range of HIV variants. HPC-derived dendritic cells (HPC-DC) were more susceptible to HIV-1 than to HIV-2 isolates. The HIV-1 group O strains were more productive in HPC-DC than group M, but amongst the latter, no subtype-related difference was observed. Both non-syncytium-inducing (NSI) and SI HIV isolates and lab strains could productively infect HPC-DC, albeit with a different efficiency. Adding blocking antibodies confirmed that both CCR-5 and CXCR-4 co-receptors were functional. Biological HIV-1 clones of the NSI/R5 phenotype infected more readily HPC-DC than SI/X4 clones. MO-derived dendritic cells were, however, more exclusive in their preference for NSI/R5 clones. Some HIV variants, that did not grow readily in HPC-DC alone, could be rescued by adding resting or pre-activated T cells. The present data show that HIV-2 isolates and SI clones replicate less in model-DC, but no preference for a particular HIV-1 subtype was evident. Co-culture with T cells could "correct" a limited growth in dendritic cells. Clearly, both intrinsic dendritic cell susceptibility and enhancement by T cells are explained only partly by HIV genotype and phenotype. The in vitro dendritic cell models seem useful tools to further unravel interactions between HIV, DC, and T cells.

Lamivudine treatment for decompensated cirrhosis resulting from chronic hepatitis B

The prognosis of decompensated cirrhosis resulting from chronic hepatitis B is poor, and the benefits of treatment with interferon are outweighed by serious side effects and by the risk of fatal exacerbation of disease activity. Lamivudine rapidly reduces hepatitis B virus (HBV)-DNA in serum to undetectable levels. We have treated 35 patients with chronic hepatitis B and decompensated cirrhosis with lamivudine 100 mg or 150 mg orally once daily. Pretreatment, all were positive for HBV-DNA in serum. Ten had Child-Pugh class B and 25 had Child-Pugh class C liver disease. Seven patients underwent liver transplantation within 6 months of treatment initiation, 5 patients died within 6 months, and 23 patients were treated for at least 6 months (mean = 19 months). In a majority of these 23 cases, there was a slow but marked improvement in liver function, which was most apparent after 9 months of treatment, with a decrease in serum bilirubin from 67 +/- 13 to 30 +/- 4 micromol/L (P <.05, baseline vs. 9 months), an increase in serum albumin from 27 +/- 1 to 34 +/- 1g/L (P <.05), and a decrease in Child-Pugh score from 10.3 +/- 0.4 to 7.5 +/- 0.5 (P <.05). Three patients developed resistance to lamivudine because of a mutation in the YMDD motif, but liver function did not deteriorate. We conclude that inhibition of viral replication with lamivudine results in a significant improvement of liver function in patients with decompensated HBV cirrhosis, but the long-term benefits remain uncertain.

Smokers can learn to influence their urge to smoke

Forty heavy smokers participated in a within-subject experiment in which the association between smoking-related cues and nicotine intake was made conditional on two neutral stimuli. Two colored cards indicated whether smoking-related cues, placed on the cards, would or would not be followed by nicotine intake. In the presence of each card, subjects were asked to rank their urge to smoke before and during the exposure to the smoking cues. The results of the present study revealed that the predictive value of a cue, in regard to the occurrence of nicotine intake, strongly determines its ability to generate craving. It was concluded that participants learned a modified predictive value of smoking cues, through a process of conditioning, and in this way influenced their urge to smoke. Furthermore, the findings suggest the reconditioning of CS-US associations as an aid in the treatment of smoking addiction.

Cefotaxime, desacetyl-cefotaxime, and bactericidal activity in spontaneous bacterial peritonitis

We have prospectively studied 13 episodes of spontaneous bacterial peritonitis (SBP) in 12 patients treated with cefotaxime (CTX) 2 g intravenously every 8 h (mean duration, 5.3 days). Ascitic fluid was inoculated at the bedside. The cultures were done before, during (day 3 after CTX initiation), and 48-72 h (mean, 56 h) after the end of therapy. All SBP episodes were monomicrobial. During treatment, the concentrations of CTX and desacetyl-cefotaxime (d-CTX) in ascitic fluid were high in all 13 SBP episodes, and d-CTX was still present in 6 patients who had residual ascitic bactericidal titer (ABT) activity after the last dose of CTX. ABTs were >/=1:128 during CTX therapy in 12 episodes and were measurable in 7 patients after the last dose. All patients were cured. The present study provides scientific rationale to the clinical studies that suggest treating SBP episodes with lower doses of antibiotics and shorter treatment duration.

Intrapatient variability of HIV type 1 group O ANT70 during a 10-year follow-up

HIV-1 ANT70 is the first HIV-1 group O virus isolate obtained from a 25-year-old Cameroonian woman, who seroconverted in March 1987. This individual has remained asymptomatic and clinically healthy (clinical stage WHO 1, CDC II) even though she did not receive any antiretroviral therapy for HIV-1 before 97 months post-seroconversion. CD4+ T cell counts declined steadily to 200/microl at 70 months postseroconversion. The HIV-1 ANT70 nucleotide and amino acid sequence diversity of the V3C3-encoding env fragment within this individual was followed over a 10-year period. RT-PCR, cloning, sequencing, and genetic analyses were performed on eight plasma follow-up samples. Extensive increasing intra- and intersample variation was observed. This is the first long-term (>10 years) follow-up of the genetic variability of an HIV-1 group O-infected individual. As the course of the disease in the HIV-1 ANT70-infected woman was similar in many aspects to that of group M-infected individuals, it remains to be elucidated whether the changes observed in the V3 loop are critical for disease progression.

Treatment of chronic bleeding from gastric antral vascular ectasia (GAVE) with estrogen-progesterone in cirrhotic patients: an open pilot study

OBJECTIVE

Gastric antral vascular ectasia (GAVE) is a rare cause of chronic bleeding in cirrhotic patients. Treatment of GAVE with surgical or nonsurgical portal decompression, beta-blockers, or endoscopic therapy provides disappointing results. In the present study, we evaluated the efficacy of estrogen-progesterone therapy, which has been reported to control chronic bleeding in gastrointestinal vascular malformations, such as Osler-Weber Rendu disease or angiodysplasia, in GAVE-related chronic bleeding.

METHODS

Six cirrhotic patients who bled chronically from GAVE were included. Three had alcoholic cirrhosis, two cryptogenic cirrhosis, and one primary biliary cirrhosis. Grade 1 esophageal varices were noted in four patients. Bleeding could not be controlled by beta-blockers, and endoscopic therapy was not considered given the extension of the antral vascular lesions.

RESULTS

Before the start of therapy, transfusion requirements averaged 3.5 units/month over a 1.5-11 month period of observation. Patients were then treated with a combination of ethynil estradiol 30 microg and noretisterone 1.5 mg daily. During follow-up (range 3-12 months), bleeding did not recur in four patients; in one patient, treatment with estrogen progesterone decreased the need for transfusions from 4 units/month to 1.4 unit/month; this patient stopped the treatment inadvertently after 6 months and severe anemia recurred with a need for 4 units of blood in the following month; reintroduction of the treatment resulted in an increase of hemoglobin levels without the need for blood transfusions during the following 4 months. In the last patient, a 5-month treatment did not improve chronic bleeding.

CONCLUSIONS

The present study suggests that estrogen-progesterone therapy is useful in the treatment of chronic bleeding related to GAVE; however, these findings require confirmation by a controlled trial.

Gastric antral vascular ectasia in cirrhotic patients: absence of relation with portal hypertension

BACKGROUND

Portal hypertensive gastropathy and gastric antral vascular ectasia (GAVE) are increasingly recognised as separate entities. The pathogenic role of portal hypertension for the development of GAVE is still controversial.

AIMS

To evaluate the effects of portal decompression on chronic bleeding related to GAVE in cirrhotic patients.

METHODS

Eight patients with cirrhosis and chronic blood loss related to GAVE were included. GAVE was defined endoscopically and histologically.

RESULTS

All patients had severe portal hypertension (mean portocaval gradient (PCG) 26 mm Hg) and chronic low grade bleeding. Seven patients underwent transjugular intrahepatic portosystemic shunt (TIPS) and one had an end to side portacaval shunt. Rebleeding occurred in seven patients. In these, TIPS was found to be occluded after 15 days in one patient; in the other six, the shunt was patent and the PCG was below 12 mm Hg in five. In the responder, PCG was 16 mm Hg. Antrectomy was performed in four non-responders; surgery was uneventful, and they did not rebleed after surgery, but two died 11 and 30 days postoperatively from multiorgan failure. In one patient, TIPS did not control GAVE related bleeding despite a notable decrease in PCG. This patient underwent liver transplantation 14 months after TIPS; two months after transplantation, bleeding had stopped and the endoscopic appearance of the antrum had normalised.

CONCLUSIONS

Results suggest that GAVE is not directly related to portal hypertension, but is influenced by the presence of liver dysfunction. Antrectomy is a therapeutic option when chronic bleeding becomes a significant problem but carries a risk of postoperative mortality.

Risk factors for acquisition of hepatitis C virus infection in blood donors: results of a case-control study

BACKGROUND & AIMS

Few studies have explored risk factors predicting hepatitis C virus (HCV) infection in blood donors; their results are contradictory. The aim of this study was to evaluate the association between HCV infection and various risk factors in Canadian volunteer blood donors.

METHODS

Four transfusion centers were involved in this case-control study. A total of 267 confirmed anti-HCV-positive blood donors were interviewed along with 1068 seronegative blood donors matched for sex, age, donation site, and date. Information was collected using a structured telephone interview. The main outcome measures were odds ratios (ORs) and 95% confidence intervals (CIs) for various risk factors from univariate and multivariate analyses using conditional logistic regression.

RESULTS

By univariate analysis, 23 variables were associated with anti-HCV positivity. In the final multivariate analysis, only 5 factors remained independently predictive of HCV infection: previous intravenous drug use (OR, 127.5; 95% CI, 26.0-625.0), having lived in a prison or juvenile detention center (56.1; 11.4-275.7), previous blood transfusion (10.5; 4.7-23.2), sexual contact with an intravenous drug user (6.9; 3.1-15.2), and tattooing (5.7; 2.5-13).

CONCLUSIONS

Most blood donors acquire infection by percutaneous exposure to contaminated blood. A role for sexual transmission is suggested by this study.

Interpatient genetic variability of HIV-1 group O

OBJECTIVE

To analyse the genetic and phylogenetic characteristics of HIV-1 group O viruses.

MATERIALS AND METHODS

The env gene, encoding the gp160 glycoprotein, and a partial p24-encoding gag gene fragment of a Cameroonian (CA9) and a Gabonese (VI686) HIV-1 group O virus, isolated from cultured peripheral blood mononuclear cells of symptomatic patients, were sequenced, aligned with other representatives of group O for which the same region has been documented, and genetically and phylogenetically analysed.

RESULTS

Phylogenetic analysis of the env gene (gp160) revealed that CA9, VI686, ANT70, and four Ha strains formed a separate cluster, which was supported by 100% of all bootstrap trees. In addition, these seven isolates were part of the same clade in the p24 phylogeny. VAU and MVP5180 may represent two other subtypes.

CONCLUSION

We have characterized two group O viruses, originating from Cameroon and Gabon, which show a close evolutionary relationship to ANT70 and four Ha strains based on the entire env gene, suggestive of a first group O subgroup, tentatively named the HIV-1 group O env ANT70 clade or subtype.

Lack of correlation between V3-loop peptide enzyme immunoassay serologic subtyping and genetic sequencing

OBJECTIVE

To compare the performance of V3-loop peptide enzyme immunoassay (PEIA) methodologies from four different laboratories for subtyping HIV-1, and to determine the causes for the lack of correlation between V3-loop PEIA serotyping and subtyping by sequencing.

MATERIALS AND METHODS

Synthetic peptides derived from the amino-acid consensus sequences of the V3-loop of group M strains representing genetic subtypes A-F as well as reference strains were evaluated in PEIA by four different laboratories for their ability to accurately determine the subtype in a panel of 85 sera obtained from persons infected with known HIV-1 subtypes (28 subtype A, 34 subtype B, four subtype C, 10 subtype D, seven subtype F, one each of subtype H and G). Furthermore, the V3 loop of the corresponding virus was compared with the V3 loop of the peptides used in PEIA.

RESULTS

The correlation between HIV-1 subtyping by sequencing and V3-loop PEIA from the different laboratories varied considerably for the different HIV-1 subtypes: subtype A (46-68%), B (38-85%), C (75-100%), D (29-50%), and F (17-57%). A 70% agreement between PEIA and sequencing subtypes was observed for samples with the concordant presence of the same octameric sequences in the V3 loop of the virus and the V3 loop of the peptide used in PEIA; however, only 42% of specimens with different V3-loop octameric viral and peptide sequences yielded concordant results in V3-loop serotyping and genetic subtyping.

CONCLUSION

Our results indicate that V3-loop PEIA methodologies used in different laboratories correlate poorly with genetic subtyping, and that their accuracy to predict HIV-1 subtypes in sera of Belgian individuals infected with different HIV-1 subtypes (A, B, C, D, F, G and H) vary considerably. The poor correlation between serotyping and genetic subtyping was partly due to the simultaneous occurrence of subtype-specific octameric sequences at the tip of the V3 loop of viruses belonging to different genetic subtypes.

Differential diagnosis of HIV type 1 group O and M infection by polymerase chain reaction and PstI restriction analysis of the pol gene fragment

HIV-1 group O serological screening or confirmation strategies so far have not proved 100% sensitive and specific, indicating a lack of antibody reactivity or cross-reactivity with group O antigens. Therefore, genetic analysis currently represents the only method by which confirm presumed HIV-1 group O or group O/M infections. We have optimized the sensitivity (100%) and specificity (100%) of an HIV-1 group O/M-specific PCR of a pol gene fragment. In addition, we report on a highly sensitive (97.2%) and specific (100%) method for differentiation between HIV-1 group O and group M viruses, using PCR and PstI enzyme restriction fragment analysis of a pol fragment. Compared with sequencing, these methods are fast, inexpensive, and simple.

Evaluation of different V3 peptides in an enzyme immunoassay for specific HIV type 1 group O antibody detection

Strategies to discriminate group O from group M infections need to be improved. We have developed and evaluated an HIV-1 group O V3 peptide-based enzyme immunoassay (PEIA) for specific HIV-1 group O antibody detection among HIV-1-infected patients. Synthetic peptides, derived from the amino acid sequences of the V3 loop of 15 different group O strains and 7 group O consensus sequences, were evaluated in a PEIA against a panel of genetically confirmed group O (n = 33), group M (n = 90), and HIV-1 antibody-negative sera (n = 17). The best-performing PEIA(s) were then used to screen 134 sera of European and 336 sera of Cameroonian origin for the presence of anti-HIV-1 group O antibodies. The reactivity of reference ("gold standard") sera to individual peptides in the PEIA resulted in the selection of five different peptides with sensitivities (sens), specificities (spec), and test efficiencies (TEs) in the range of 90 to 100%. Improvement of the PEIA was obtained with simultaneous reactivity of at least two different peptides in separate wells of an ELISA plate, together with stringent criteria for positivity. We were able to select seven peptide combinations each with a sens, spec, and TE of 96.9, 100, and 99.2%, respectively. None of the 134 European and 4 (1.2%) of the 336 Cameroonian samples sera were group O positive in the optimized HIV-1 group O PEIA; this was confirmed by the repeated presence of reactives, in agreement with the present knowledge of group O infection distribution. Finally, we were able to develop a strategy with a higher TE (99.2%) than the previously used ANT-70 (98.5%) and ANT-70/MVP5180 (95.7%). Our results show that optimal specificity rather than optimal sensitivity makes the V3 PEIA a sufficiently accurate epidemiological tool to be useful in estimating specifically group O infection among HIV-1-infected patients.

Design and evaluation of an in-house HIV-1 (group M and O), SIVmnd and SIVcpz antigen capture assay

An enzyme-linked immuno-sorbent assay (ELISA) for the detection of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIVcpz/SIVmnd) antigens was designed using immunoreagents from naturally infected individuals, and compared to the commercially available Vironostika HIV-1 Antigen Microelisa System (Organon Teknika). The in-house assay proved to be specific for HIV-1 isolates belonging to group M (A-H) and group O and for SIVcpz and SIVmnd isolates, but was less sensitive than the Vironostika HIV-1 Antigen Microelisa System, except for SIVmnd. For the strains belonging to HIV-2, SIVmac and SIVagm, the in-house assay could not detect antigen to an appreciable degree. This study shows that a considerably less expensive but sufficiently accurate HIV-1 antigen capture assay can be developed to monitor HIV-1 (group M and O), SIVcpv and SIVmnd antigen in the supernatants of virus cultures.

Lack of relationship between preoperative measures of the severity of cirrhosis and short-term survival after liver transplantation

The purpose of this study was to evaluate the prognostic value of clinical measures of the severity of disease in cirrhotic patients who were candidates for liver transplantation at our institution. The records of the 132 cirrhotic patients who were candidates for a first transplantation between January 1, 1987, and December 31, 1994, were reviewed. One hundred nine patients (82.6%) received grafts, and 23 (17.4%) died while on the waiting list. The variables examined included level of medical urgency at the time of enlistment, date of transplantation, serum creatinine level, variables that constitute the Child-Pugh score and Shaw's risk score (serum bilirubin and albumin, prothrombin time, ascites, encephalopathy, nutritional status, age, and operative blood loss), and 6-month survival status after transplantation. The proportion of patients who died awaiting a graft increased as a function of the Child-Pugh score at enlistment (score 5-6, 0%, n = 6; score 7-9, 7%, n = 54; score 10-11, 18%, n = 33; score 12-15, 33%, n = 39; P = .01). Six-month survival rates after transplantation were similar irrespective of the Child-Pugh score or Shaw's risk score. Stepwise multiple logistic regression models identified the degree of ascites, serum bilirubin, and operative blood loss as significant variables for the prediction of overall mortality 6 months posttransplantation (model chi 2 = 12.8; P = .025; r = 0.32), but the model explained only 10% of the outcomes observed. We concluded that the Child-Pugh score is a valid prognostic index for survival up to the time of transplantation for cirrhotic patients on the waiting list; however, clinical measures of the severity of cirrhosis are poor predictors of 6-month survival after transplantation.

Quantitative assessment of serum hepatitis B e antigen, IgM hepatitis B core antibody and HBV DNA in monitoring the response to treatment in patients with chronic hepatitis B

Virological response to treatment of chronic hepatitis B is defined as the loss of serum hepatitis B virus DNA (HBV DNA) and hepatitis B e antigen (HBeAg). The quantitative measurement of HBV DNA is useful for monitoring and predicting the response to therapy with interferon-alpha (IFN-alpha). In this study, we evaluated whether quantitative measurement of serum HBeAg and IgM antibody to hepatitis B core antigen (HBcAb) could also be used in this manner. Using a microparticle-capture enzyme immunoassay (IMx), a standard curve of fluorescence rate vs HBeAg concentration was constructed to provide quantitative results. The IgM HBcAb index was also measured using a microparticle enzyme immunoassay and serum HBV DNA was measured by a solution hybridization assay. We studied 48 patients who were initially positive for HBeAg and HBV DNA and who were treated with IFN-alpha2b. Their sera were serially evaluated for HBeAg concentration, and results were compared with HBV DNA levels. In the 14 patients who responded to IFN, similar disappearance curves were observed with good intraindividual correlation between the levels of the two markers. In the 34 non-responders, HBeAg levels decreased during treatment but never became negative; HBV DNA levels also decreased during treatment and became transiently undetectable in six patients, falsely suggesting treatment success. The IgM HBcAb index paralleled changes in alanine aminotransferase (ALT) concentration and did not provide additional information. Multiple logistic regression indicated that baseline ALT and HBeAg concentrations were independent predictors of the response to treatment and the addition of neither HBV DNA nor IgM HBcAb improved the model. We conclude that quantitative measurement of HBeAg provides information similar to that of HBV DNA in monitoring and predicting the response to treatment; this technique could be readily adaptable to clinical laboratories.