An accurate definition of the status of inactive hepatitis B virus carrier by a combination of biomarkers (FibroTest-ActiTest) and viral load

Background

The combination of transaminases (ALT), biopsy, HBeAg and viral load have classically defined the inactive status of carriers of chronic hepatitis B. The use of FibroTest (FT) and ActiTest (AT), biomarkers of fibrosis and necroinflammatory activity, has been previously validated as alternatives to biopsy. We compared the 4-year prognostic value of combining FT-AT and viral load for a better definition of the inactive carrier status.

Methods and Findings

1,300 consecutive CHB patients who had been prospectively followed since 2001 were pre-included. The main endpoint was the absence of liver-related complications, transplantation or death. We used the manufacturers'' definitions of normal FT (< = 0.27), normal AT (< = 0.29) and 3 standard classes for viral load. The adjustment factors were age, sex, HBeAg, ethnic origin, alcohol consumption, HIV-Delta-HCV co-infections and treatment.

Results

1,074 patients with baseline FT-AT and viral load were included: 41 years old, 47% African, 27% Asian, 26% Caucasian. At 4 years follow-up, 50 complications occurred (survival without complications 93.4%), 36 deaths occurred (survival 95.0%), including 27 related to HBV (survival 96.1%). The prognostic value of FT was higher than those of viral load or ALT when compared using area under the ROC curves [0.89 (95%CI 0.84–0.93) vs 0.64 (0.55–0.71) vs 0.53 (0.46–0.60) all P<0.001], survival curves and multivariate Cox model [regression coefficient 5.2 (3.5–6.9; P<0.001) vs 0.53 (0.15–0.92; P = 0.007) vs −0.001 (−0.003−0.000;P = 0.052)] respectively. A new definition of inactive carriers was proposed with an algorithm combining “zero” scores for FT-AT (F0 and A0) and viral load classes. This new algorithm provides a 100% negative predictive value for the prediction of liver related complications or death. Among the 275 patients with the classic definition of inactive carrier, 62 (23%) had fibrosis presumed with FT, and 3 died or had complications at 4 year.

Conclusion

In patients with chronic hepatitis B, a combination of FibroTest-ActiTest and viral load testing accurately defined the prognosis and the inactive carrier status.     

Optogenetic manipulation of cyclic guanosine monophosphate to probe phosphodiesterase activities in megakaryocytes

Cyclic guanosine monophosphate (cGMP) signalling plays a fundamental role in many cell types, including platelets. cGMP has been implicated in platelet formation, but mechanistic detail about its spatio-temporal regulation in megakaryocytes (MKs) is lacking. Optogenetics is a technique which allows spatio-temporal manipulation of molecular events in living cells or organisms. We took advantage of this method and expressed a photo-activated guanylyl cyclase, Blastocladiella emersonii Cyclase opsin (BeCyclop), after viral-mediated gene transfer in bone marrow (BM)-derived MKs to precisely light-modulate cGMP levels. BeCyclop-MKs showed a significantly increased cGMP concentration after illumination, which was strongly dependent on phosphodiesterase (PDE) 5 activity. This finding was corroborated by real-time imaging of cGMP signals which revealed that pharmacological PDE5 inhibition also potentiated nitric oxide-triggered cGMP generation in BM MKs. In summary, we established for the first-time optogenetics in primary MKs and show that PDE5 is the predominant PDE regulating cGMP levels in MKs. These findings also demonstrate that optogenetics allows for the precise manipulation of MK biology.     

Wave front migration of endothelial cells in a bone-implant interface

The neo-vascularization of the host site is crucial for the primary fixation and the long-term stability of the bone-implant interface. Our aim was to investigate the progression of endothelial cell population in the first weeks of healing. We proposed a theoretical reactive model to study the role of initial conditions, random motility, haptotaxis and chemotaxis in interactions with fibronectin factors and transforming angiogenic factors. The application of governing equations concerned a canine experimental implant and numerical experiments based upon statistical designs of experiments supported the discussion. We found that chemotaxis due to transforming angiogenic factors was attracting endothelial cells present into the host bone. Haptotaxis conditioned by fibronectin factors favored cells adhesion to the host bone. The combination of diffusive and reactive effects nourished the wave front migration of endothelial cells from the host bone towards the implant. Angiogenesis goes together with new-formed bone formation in clinics, so the similarity of distribution patterns of mineralized tissue observed in-vivo and the spatio-temporal concentration of endothelial cells predicted by the model, tended to support the reliability of our theoretical approach.     

In Vivo Formation and Binding of SeHg Complexes to the Erythrocyte Surface

The in vivo dynamics of selenium (Se) and mercury (Hg) interaction was studied in mouse tissues using direct visualization of individual Se, Hg, and SeHg particles on the surface of circulating erythrocytes. This high-resolution detection of Se and Hg was obtained by scanning electron microscopy coupled to X-ray microanalysis. BALB/c mice were injected in the peritoneal cavity with Se and Hg salts, and the animals were sacrificed 3 min after the Hg injection. Only a minority (9%) of the metal dots seen on mouse liver erythrocytes were SeHg complexes when Se and Hg salts were mixed together before injection. In contrast, the majority (73%) of metal dots on liver erythrocytes were SeHg complexes if Se was injected at least 5 min before Hg injection. All metal dots on liver erythrocytes were of SeHg complexes if Se was injected 9 or 12 min before the Hg injection. We conclude that the formation of stable in vivo SeHg complexes requires preliminary interaction of Se with a putative serum factor before complexes between Se and Hg are formed and are bound to the erythrocyte cell surface.     

The manifold characters of orbicules: structural diversity,systematic significance,and vectors for allergens

In the anthers of flowering plants, gymnosperms, and seed ferns, tiny (±1?μm) granules might occur on the radial and innermost tangential wall of secretory tapetum cells. These sporopollenin granules develop simultaneously with the pollen exine and are called orbicules or Ubisch bodies. The present paper focuses on two quite different topics associated with orbicules.

The morphological and ultrastructural diversity of orbicules in the order Gentianales is summarized, and it is demonstrated that orbicules are a plesiomorphic feature in the order. Furthermore, orbicule characters seemed to be correlated with evolutionary trends in pollen dispersal unit and tapetum type features.

In the second part, we report on our investigation of Corylus avellana L. (Hazel) pollen, using immunogold electron microscopy to gain an insight into the possible role that orbicules may play as a vector of pollen allergens. During the pollen season orbicules are dispersed into the atmosphere along with Hazel pollen grains. The localisation of homologues of the new birch pollen allergen Bet v 7 was studied at the subcellular level in Hazel anthers. The results of this study indicate that orbicules and pollen of Hazel might act as very effective vectors for homologues of Bet v 7 and that debris of Hazel anthers represent vectors of allergens after the pollen season.     

Hypoxic alterations of cortisol circadian rhythm in man after simulation of a long duration flight

Fatigue is often reported after long duration flights. Mild hypobaric hypoxia caused by pressurisation may be involved in this effect through disruption of circadian rhythms, independently of the number of time zones crossed. In this controlled crossover study, we assessed the effects of two levels of hypoxia equivalent to 8000 and 12,000 ft on the circadian rhythm of plasma cortisol, a marker of the circadian time structure. Sixteen healthy young male volunteers (23-39 years) were exposed in a hypobaric chamber for 8 h (08:00-16:00 h) to 8000 ft, followed 4 weeks later to 12,000 ft. Plasma cortisol was assayed during two 24-h cycles (control and hypoxic exposure) every 2h in all subjects. We found a significant change in the pattern of cortisol secretion during both hypoxic exposures, with an initial fall in cortisol followed by a transient rebound, whereas the phase and the 24-h mean level remained unchanged. The change in cortisol pattern followed the alterations in autonomic balance assessed by heart rate variability (HRV) spectral analysis. The normalised high frequencies and the low-to-high frequencies ratio showed a significant shift toward sympathetic dominance with some differences in time course for both altitudes studied. HRV analysis improved the interpretation of cortisol 24-h profiles. Our data, which strongly suggest that prolonged mild hypoxia alters the expression of cortisol circadian rhythm, should be taken into account to interpret secretory rhythm changes after transmeridian flights.     

Analyses of the Temporal Dynamics of Fungal Communities Colonizing the Healthy Wood Tissues of Esca Leaf-Symptomatic and Asymptomatic Vines

Esca, a Grapevine Trunk Disease (GTD), is of major concern for viticulture worldwide. Our study compares the fungal communities that inhabit the wood tissues of vines that expressed or not foliar esca-symptoms. The trunk and rootstock tissues were apparently healthy, whether the 10 year-old plants were symptomatic or not. The only difference was in the cordon, which contained white rot, a typical form of esca, in 79% of symptomatic plants. Observations over a period of one year using a fingerprint method, Single Strand Conformation Polymorphism (SSCP), and the ITS-DNA sequencing of cultivable fungi, showed that shifts occurred in the fungal communities colonizing the healthy wood tissues. However, whatever the sampling time, spring, summer, autumn or winter, the fungi colonizing the healthy tissues of asymptomatic or symptomatic plants were not significantly different. Forty-eight genera were isolated, with species of Hypocreaceae and Botryosphaeriaceae being the most abundant species. Diverse fungal assemblages, made up of potentially plant-pathogenic and -protective fungi, colonized these non-necrotic tissues. Some fungi, possibly involved in GTD, inhabited the non-necrotic wood of young plants, but no increase in necrosis areas was observed over the one-year period.