Predictive Factors for Sustained Virological Response after Treatment with Pegylated Interferon α-2a and Ribavirin in Patients Infected with HCV Genotypes 2 and 3

Background

Previous trials have often defined genotype 2 and 3 patients as an “easy to treat” group and guidelines recommend similar management.

Aims

The present study looks for differences between the two genotypes and analyzes predictive factors for SVR.

Methods

Prospective, community-based cohort study involving 421 physicians throughout Germany. The analysis includes 2,347 patients with untreated chronic HCV genotype 2 (n = 391) and 3 (n = 1,956) infection treated with PEG-IFN α-2a plus ribavirin between August 2007 and July 2012.

Results

When compared with genotype 2 patients, those with genotype 3 were younger, had a shorter duration of infection, lower values of total cholesterol, LDL cholesterol and BMI, a higher frequency of drug use as infection mode and male gender (p<0.0001, respectively), and a higher APRI score (p<0.005). SVR was higher in genotype 2 when compared with genotype 3 (64.7% vs. 56.9%, p = 0.004). By multivariate analysis of genotype 2 patients, low baseline γ -GT and RVR predicted SVR. In genotype 3 age ≤45 years, cholesterol>130 mg/dl, a low APRI score, and a γ-GT ≥3-times ULN, RVR, and RBV starting dose were associated with SVR by multivariate analysis.

Conclusions

The present study corroborates that liver fibrosis is more pronounced in genotype 3 vs. 2. SVR is higher in genotype 2 versus genotype 3 partly because of follow-up problems in genotype 3 patients, in particular in those infected by drug use. Thus, subgroups of genotype 3 patients have adherence problems and need special attention also because they often have significant liver fibrosis.

Trial Registration

Verband Forschender Arzneimittelhersteller e.V., Berlin, Germany ML21645 ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT02106156","term_id":"NCT02106156"}}NCT02106156     

Short communication. Comparative measurements of xylem pressure in transpiring and non-transpiring leaves by means of the pressure chamber and the xylem pressure probe

Simultaneous measurements were made with the xylem pressure probe on exposed, transpiring leaves and with the Scholander pressure chamber on both transpiring and covered, non-transpiring leaves of sugarcane and maize plants. Xylem tensions inferred from pressure chamber balancing pressures on non-transpiring leaves were similar to those measured directly with the xylem pressure probe in transpiring leaves. However, tensions inferred with the pressure chamber on transpiring leaves that were placed in plastics bags just prior to excision were up to 0.6 MPa greater than those measured concurrently with the xylem pressure probe. These findings suggest that relatively large differences in water potential between the xylem and bulk leaf tissue can exist during periods of rapid transpiration, and they confirm that the balance pressure of an excised, previously transpiring leaf is only a measure of the bulk average equilibrium leaf water potential and not of the true xylem pressure that existed prior to excision.Key words: Cohesion-Tension theory, xylem pressure probe, pressure chamber, xylem tension.      

ATP and acetylcholine, equal brethren

Acetylcholine was the first neurotransmitter identified and ATP is the hitherto final compound added to the list of small molecule neurotransmitters. Despite the wealth of evidence assigning a signaling role to extracellular ATP and other nucleotides in neural and non-neural tissues, the significance of this signaling pathway was accepted very reluctantly. In view of this, this short commentary contrasts the principal molecular and functional components of the cholinergic signaling pathway with those of ATP and other nucleotides. It highlights pathways of their discovery and analyses tissue distribution, synthesis, uptake, vesicular storage, receptors, release, extracellular hydrolysis as well as pathophysiological significance. There are differences but also striking similarities. Comparable to ACh, ATP is taken up and stored in synaptic vesicles, released in a Ca(2+)-dependent manner, acts on nearby ligand-gated or metabotropic receptors and is hydrolyzed extracellularly. ATP and acetylcholine are also costored and coreleased. In addition, ATP is coreleased from biogenic amine storing nerve terminals as well as from at least subpopulations of glutamatergic and GABAergic terminals. Both ACh and ATP fulfill the criteria postulated for neurotransmitters. More recent evidence reveals that the two messengers are not confined to neural functions, exerting a considerable variety of non-neural functions in non-innervated tissues. While it has long been known that a substantial number of pathologies originate from malfunctions of the cholinergic system there is now ample evidence that numerous pathological conditions have a purinergic component.     

Geographic differences for delay of sexual maturation in Peromyscus leucopus: effects of photoperiod, pinealectomy, and melatonin

Effects of short-day photoperiod, pinealectomy, and melatonin on sexual maturation were tested in Peromyscus leucopus from either Connecticut (CT) or Georgia (GA). Laboratory reared-stocks from CT and GA were exposed to short daylength (photoperiod) from birth or 25 days of age. At 12 wk of age, delay in sexual maturation was indicated in most CT mice by decreased testis length, combined testes weight, and seminal vesicle weight. Conversely, GA animals did not delay sexual maturation when exposed to short-day photoperiod from either birth or 25 days of age. These results indicate that responses to short daylengths differ for juvenile CT and GA populations. In a second experiment, pinealectomized or sham-operated CT males were exposed to short-day (9L:15D) or long-day (16L:8D) photoperiod from birth. Pinealectomy blocked the effect of short daylength on reproduction. Therefore, the pineal must be involved in the delay of sexual maturation observed for short-day CT mice. The effects of melatonin, a pineal gland hormone, were tested with chronic s.c. implants or daily injections. In CT mice given either melatonin implants or afternoon injections, sexual maturation was delayed. GA mice were insensitive to all melatonin treatments. Further, no differences in circadian organization (phase angle, duration of activity, period under constant dark) between GA and CT animals were apparent. Collectively, these studies indicate that melatonin is involved in the mechanism responsible for delay of sexual maturation in CT mice. Short-day insensitivity of GA Peromyscus leucopus probably results from a deficiency in the melatonin effector pathway and is not due to a disruption of circadian organization.     

Synthesis and characterization of fluorescent ubiquitin derivatives as highly sensitive substrates for the deubiquitinating enzymes UCH-L3 and USP-2

Deubiquitinating enzymes (DUBs) catalyze the removal of attached ubiquitin molecules from amino groups of target proteins. The large family of DUBs plays an important role in the regulation of the intracellular homeostasis of different proteins and influences therefore key events such as cell division, apoptosis, etc. The DUB family members UCH-L3 and USP2 are believed to inhibit the degradation of various tumor-growth-promoting proteins by removing the trigger for degradation. Inhibitors of these enzymes should therefore lead to enhanced degradation of oncoproteins and may thus stop tumor growth. To develop an enzymatic assay for the search of UCH-L3 and USP2 inhibitors, C-terminally labeled ubiquitin substrates were enzymatically synthesized. We have used the ubiquitin-activating enzyme E1 and one of the ubiquitin-conjugating enzymes E2 to attach a fluorescent lysine derivative to the C terminus of ubiquitin. Since only the epsilon-NH(2) group of the lysine derivatives was free and reactive, the conjugates closely mimic the isopeptide bond between the ubiquitin and the lysine side chains of the targeted proteins. Various substrates were synthesized by this approach and characterized enzymatically with the two DUBs. The variant consisting of the fusion protein between the large N-terminal NusA tag and the ubiquitin which was modified with alpha-NH(2)-tetramethylrhodamin-lysine, was found to give the highest dynamic range in a fluorescence polarization readout. Therefore we have chosen this substrate for the development of a miniaturized, fluorescence-polarization-based high-throughput screening assay.     

Metal-protein complex-mediated transport and delivery of Ni2+ to TCR/MHC contact sites in nickel-specific human T cell activation

Nickel allergy clearly involves the activation of HLA-restricted, skin-homing, Ni-specific T cells by professional APCs. Nevertheless, knowledge concerning the molecular details of metal-protein interactions underlying the transport and delivery of metal ions to APC during the early sensitization phase and their interactions with HLA and TCRs is still fragmentary. This study investigates the role of human serum albumin (HSA), a known shuttling molecule for Ni(2+) and an often-disregarded, major component of skin, in these processes. We show that Ni-saturated HSA complexes (HSA-Ni) induce and activate Ni-specific human T cells as potently as Ni salt solutions when present at equimolar concentrations classically used for in vitro T cell stimulation. However, neither HSA itself nor its Ni-binding N-terminal peptide are involved in determining the specificity of antigenic determinants. In fact, HSA could be replaced by xenogeneic albumins exhibiting sufficient affinity for Ni(2+) as determined by surface plasmon resonance (Biacore technology) or atomic absorption spectroscopy. Moreover, despite rapid internalization of HSA-Ni by APC, it was not processed into HLA-associated epitopes recognizable by Ni-specific T cells. In contrast, the presence of HSA-Ni in the vicinity of transient contacts between TCR and APC-exposed HLA molecules appeared to facilitate a specific transfer of Ni(2+) from HSA to high-affinity coordination sites created at the TCR/HLA-interface.     

Intracellular Delivery of Carbohydrates into Mammalian Cells through Swelling-activated Pathways

Volume changes of human T-lymphocytes (Jurkat line) exposed to hypotonic carbohydrate-substituted solutions of different composition and osmolality were studied by videomicroscopy. In 200 mOsm media the cells first swelled within 1–2 min and then underwent regulatory volume decrease (RVD) to their original isotonic volume within 10–15 min. RVD also occurred in strongly hypotonic 100 mOsm solutions of di- and trisaccharides (trehalose, sucrose, raffinose). In contrast to oligosaccharide media, 100 mOsm solutions of monomeric carbohydrates (glucose, galactose, inositol and sorbitol) inhibited RVD. The complex volumetric data were analyzed with a membrane transport model that allowed the estimation of the hydraulic conductivity and volume-dependent solute permeabilities. We found that under slightly hypotonic stress (200 mOsm) the cell membrane was impermeable to all carbohydrates studied here. Upon osmolality decrease to 100 mOsm, the membrane permeability to monomeric carbohydrates increased dramatically (apparently due to channel activation caused by extensive cell swelling), whereas oligosaccharide permeability remained very poor. The size-selectivity of the swelling-activated sugar permeation was confirmed by direct chromatographic measurements of intracellular sugars. The results of this study are of interest for biotechnology, where sugars and related compounds are increasingly being used as potential cryo- and lyoprotective agents for preservation of rare and valuable mammalian cells and tissues.This revised version was published online in June 2005 with a corrected cover date.     

Ventral rectus fascia closure on top of mesh hernia repair in the sublay technique

Sublay prosthetic herniorrhaphy has become a widely accepted procedure for incisional hernias. To evaluate the effect of fascia closure on top of mesh repair on infection, and the recurrence rate, the authors reviewed their data regarding herniorrhaphy in the sublay technique. This study was a retrospective analysis of 175 consecutive patients who underwent hernia repair by implantation of prostheses by means of the Stoppa-Rives technique from December of 1994 to December of 2001. All 175 patients had the mesh implanted in the subfascial plane, 130 received a light-weight or heavy-weight polypropylene mesh (Vypro or Prolene) (74 percent), eight had a polyester mesh (Mersilene) (5 percent), and 37 had an expanded polytetrafluoroethylene patch (Gore-Tex) (21 percent). After sublay mesh positioning, the mesh could not be covered by the fascia in 50 cases; in 31 of these cases, a second mesh was placed into the fascial defect. To evaluate the influence of the fascia closing procedure on top of the sublay mesh, three groups were differentiated: initial fascia closure (n = 125), no fascia closure and concomitant mesh interposition (n = 31), and no fascia closure without mesh interposition (n = 19). After a mean follow-up of 20 months, 11 deep prosthetic infections (8 percent) and 15 hernia recurrences (9 percent) were observed. There was an increased risk of mesh infection when the fascia could not be closed, but there was no influence of fascia closure on hernia recurrence. When the fascia was left open, the placement of a second mesh inlay technique reduced mesh infection. The authors' data give evidence that closing the ventral fascia after mesh repair in the sublay position is beneficial. When the edges of the hernia defect could not be approximated, the suturing of a second mesh into the fascia defect was a useful tool for reducing the prosthetic infection rate; however, no significant influence on hernia recurrence was observed.