Treatment of hepatitis C: critical appraisal of the evidence

Chronic hepatitis C virus infection is currently the most common cause of end stage liver disease worldwide. Although the conclusions of the last National Institutes of Health Consensus Development Conferences on Hepatitis C have recently been published, several important issues remain unanswered. This paper reviews the available data using an evidence-based approach. Current evidence is sufficient to recommend IFN treatment for all patients with acute hepatitis. A later initiation of therapy yields the same likelihood of response as early treatment. A daily induction dose during month 1 is the best treatment option. The current gold standard of efficacy for treatment-naive patients with chronic hepatitis C is the combination of pegylated IFN and ribavirin. The overall sustained viral response rate to these regimens is 54 - 56% following a 48-week course of therapy. Patients with genotype 1 infection will have a 42 - 51% likelihood of response to 48weeks of therapy. Those with genotypes 2 or 3 infection will respond to 24weeks in 78 - 82% of cases. Debate continues regarding the optimal dose and duration of peginterferon (PEG-IFN), not only in patients infected with genotype 2 or 3 but also in those infected with genotype 1. The optimal dose of ribavirin has yet to be determined. Available data show the need to give the highest tolerable doses (1000-1200mg/day) to the difficult-to-treat patients (genotype 1, cirrhotics, obese), although there is a greater likelihood of intolerance. Genotypes 2 and 3 may receive 800mg/day, which is also the most appropriate lower dose for those patients who require dosage modification for anaemia or other side effects. Tolerability and compliance to therapy are still a problem, as approximately 15- 20% of patients within trials and > 25% in clinical practice withdraw from therapy. New PEG-IFNs are more effective than conventional IFN in improving liver histology. Monotherapy with PEG-IFN induces a marked reduction in staging in virological sustained responders, and to a lesser degree in relapsers, but provides no benefit to nonresponders after 24-48weeks of treatment. The use of maintenance therapy in virological nonresponders aiming to improve histology should be considered experimental and of unproven benefit. Pooling data from the literature suggests a slight preventive effect of IFN on hepatocellular carcinoma development in patients with HCV-related cirrhosis. The magnitude of this effect is low and the observed benefit may be due to spurious associations. The preventive effect is more evident among sustained responders to IFN.     

Alcohol,alcoholic beverages,and melanoma risk: a systematic literature review and dose–response meta-analysis

Purpose

Several studies in recent years have investigated the relationship between alcohol intake and melanoma risk, with conflicting results. To help clarify this issue, we conducted a literature review and dose–response meta-analysis of studies published until June 30th, 2017, that examined the association between alcohol intake (overall and by beverage type) and melanoma risk.

Methods

We used random effect models with maximum likelihood estimation to calculate summary relative risk (SRR) and 95% confidence intervals (95%CI).

Results

We included 20 independent studies (encompassing 10,555 melanoma cases and over 1.6 million non-cases/controls) published during 1986–2016, of which six had a prospective cohort study design. Adjustment for phenotypic characteristics and sunlight exposure was performed in 11 and nine studies, respectively. Alcohol intake was moderately associated with melanoma risk: the SRR were 1.29 (95% CI 1.14–1.45) for those in the highest vs. lowest category of current alcohol intake, and 1.96 (95% CI 1.02–3.76, I²?=?0%) for cumulative intake. In the dose–response analysis, the increase in risk associated with a 10 g increment in daily alcohol intake was 1.07 (95% CI 1.03–1.11). Risk estimates did not differ by gender, study design and adjustment for confounders; between-studies heterogeneity was acceptable, and there was no evidence of publication bias.

Conclusions

Our findings suggest that alcohol drinking may be moderately associated with increased melanoma risk, although residual confounding and bias cannot be ruled out. Further research is needed to confirm these findings, clarify the role of the different alcohol sources, and investigate the interaction with known melanoma risk factors.

     

Serological methods used for rabies post vaccination surveys: An analysis

The assessment of fox immunity following oral rabies vaccination (ORV) is commonly applied to assess the efficacy of an ORV campaign in the field. Several ELISA kits have been developed and validated for their use for rabies serology in wildlife as an alternative to neutralizing techniques (NT), such as the fluorescent antibody virus neutralization test (FAVN) and the rapid fluorescent foci inhibition test (RFFIT). At a European level, NT and ELISA tests are used interchangeably and on different types of samples collected for vaccination follow-up. This has resulted in a difficulty in comparing the results generated with different diagnostic tools. We have evaluated (a) the effect of two different matrices commonly used for serology in red foxes on the results of the FAVN and (b) the performance of two commercially available ELISAs in comparison with the FAVN, as a gold standard, using a panel of over 700 field fox samples. Moderate agreement was observed when comparing results from different matrices. We found a very low level of agreement and low values of relative sensitivity and specificity of the ELISAs tested in comparison with the FAVN. Our findings confirm, using a vast collection of field samples obtained during post-vaccination surveillance campaigns in Italy, the need for improved reliability of certain serological tests.     

Towards resorbable 3D-printed scaffolds for craniofacial bone regeneration

This review will briefly examine the development of 3D-printed scaffolds for craniofacial bone regeneration. We will, in particular, highlight our work using Poly(L-lactic acid) (PLLA) and collagen-based bio-inks. This paper is a narrative review of the materials used for scaffold fabrication by 3D printing. We have also reviewed two types of scaffolds that we designed and fabricated. Poly(L-lactic acid) (PLLA) scaffolds were printed using fused deposition modelling technology. Collagen-based scaffolds were printed using a bioprinting technique. These scaffolds were tested for their physical properties and biocompatibility. Work in the emerging field of 3D-printed scaffolds for bone repair is briefly reviewed. Our work provides an example of PLLA scaffolds that were successfully 3D-printed with optimal porosity, pore size and fibre thickness. The compressive modulus was similar to, or better than, the trabecular bone of the mandible. PLLA scaffolds generated an electric potential upon cyclic/repeated loading. The crystallinity was reduced during the 3D printing. The hydrolytic degradation was relatively slow. Osteoblast-like cells did not attach to uncoated scaffolds but attached well and proliferated after coating the scaffold with fibrinogen. Collagen-based bio-ink scaffolds were also printed successfully. Osteoclast-like cells adhered, differentiated, and survived well on the scaffold. Efforts are underway to identify means to improve the structural stability of the collagen-based scaffolds, perhaps through mineralization by the polymer-induced liquid precursor process. 3D-printing technology is promising for constructing next-generation bone regeneration scaffolds. We describe our efforts to test PLLA and collagen scaffolds produced by 3D printing. The 3D-printed PLLA scaffolds showed promising properties akin to natural bone. Collagen scaffolds need further work to improve structural integrity. Ideally, such biological scaffolds will be mineralized to produce true bone biomimetics. These scaffolds warrant further investigation for bone regeneration.     

Biomarkers of dietary intake of micronutrients modulate DNA adduct levels in healthy adults

DNA adducts, a reliable indicator of internal dose exposure to genotoxic agents and, possibly, of cancer risk, have been shown to be modulated by diet, particularly by the consumption of fresh fruit and vegetables, and by the intake of antioxidants (Palli et al., 2000, Int. J. Cancer, 87, 444-451). We have therefore investigated the association between DNA adducts in peripheral leukocytes and plasma levels of selected micronutrients, also taking into account the role of metabolic polymorphisms and smoking history, in a large independent random sample of volunteers enrolled in the prospective study EPIC-Italy (approximately 110 subjects from each of the three main geographical study areas, Northern, Central and Southern Italy). DNA adducts and five polymorphic metabolic genotypes were determined in peripheral leukocytes using the (32)P-post-labelling technique and PCR methods. Plasma levels of six carotenoids, retinol and alpha- and gamma-tocopherol were determined in the same blood sample. Among 331 subjects, 78.3% had detectable levels of DNA adducts (mean 7.46 +/- 0.48 per 10(9) nucleotides). Vitamin supplementation was reported by only a few subjects (3.9%). Strong inverse associations emerged between levels of DNA adducts and plasma retinol (P = 0.02), alpha-tocopherol (P = 0.04) and gamma-tocopherol (P = 0.03), but not carotenoids (except a borderline inverse association with beta-carotene, P = 0.08). An inverse significant association with plasma levels of retinol and gamma-tocopherol persisted in the subgroup of non-smokers, whereas a negative association with alpha-tocopherol emerged only in smokers. DNA adduct levels did not show any significant variation according to analyzed genotypes. Stratification by GSTM1 genotype, however, showed a significant negative association between DNA adduct levels and plasma levels of alpha- (P = 0.02) and beta-carotene (P = 0.02) in subjects with the GSTM1 null genotype. Our results confirm that biomarkers of dietary intake of antioxidants significantly modulate DNA adducts and suggest specific inverse associations between DNA adduct levels and antioxidant concentrations among GSTM1 null subjects and smokers.     

Delayed effects of chronic cortisol treatment on brain and plasma concentrations of corticotropin (ACTH) and beta-endorphin

The effects of 2-day and 7-day cortisol treatment on immunoreactive corticotropin (ACTH) and beta-endorphin concentrations were measured in the cerebral cortex, hippocampus, hypothalamus, and cerebellum in male rats. Plasma ACTH, beta-endorphin, corticosterone, and cortisol levels were also measured in parallel. Cortisol administration by osmotic minipumps (25 mg/kg/day) maintained a constant, moderately high concentration (23.0 +/- 2.7 micrograms/100 ml) of this glucocorticoid in plasma. Two-day cortisol treatment suppressed the plasma concentration of ACTH and corticosterone, and also decreased, to a lesser degree, concentrations of beta-endorphin. ACTH and beta-endorphin levels in the brain remained unchanged after 2 days of cortisol treatment. After 7-day treatment, however, plasma concentrations of ACTH and beta-endorphin further decreased, while ACTH and beta-endorphin concentrations in the cortex and beta-endorphin concentrations in the cerebellum were also significantly decreased. Peptide concentrations in other brain areas did not change significantly with either 2-day or 7-day cortisol treatment. These data suggest that there are delayed effects of glucocorticoids on pro-opiomelanocortin peptide secretion and/or metabolism in the central nervous system. These findings are consistent with the impaired cognitive functions of patients with diseases, such as Cushing's syndrome and depression, that have long-lasting elevated cortisol secretion.     

Catecholamine effects upon rat hypothalamic corticotropin-releasing hormone secretion in vitro.

To further our understanding of the functional role of catecholaminergic systems in regulating hypothalamic corticotropin-releasing hormone (CRH) secretion, we assessed the direct effects of a multiplicity of catecholamine agonists and antagonists on hypothalamic CRH secretion. To accomplish this, we used an in vitro rat hypothalamic organ culture system in which CRH secretion from single explants was evaluated by a specific RIA (IR-rCRH). Norepinephrine (NE) stimulated IR-rCRH secretion dose dependently, with peak effects in the nanomolar range. The effect of NE was antagonized by the mixed alpha antagonist phentolamine, the alpha 1 antagonist prazosin, and the alpha 2 antagonist yohimbine, but not by the beta blocker, L-propanolol. Compatible with these data were the findings that the alpha 1 agonist phenylephrine and the alpha 2 agonist clonidine both stimulated IR-rCRH secretion in a dose-dependent fashion. On the other hand, whereas the beta agonist, isoproterenol, caused a weak, non-dose-dependent increase in IR-rCRH secretion, this effect could not be antagonized by L-propanolol. Despite pretreatment with serotonin and acetylcholine antagonists, the effect of NE upon IR-rCRH secretion was undiminished, suggesting that NE-induced CRH secretion is not mediated by either neurotransmitter. On the other hand, pretreatment with gamma-aminobutyric acid (GABA) attenuated NE-induced IR-rCRH secretion. Whereas epinephrine (E) stimulated IR-rCRH secretion, this occurred only at higher concentrations, and was antagonized by phentolamine, but not by L-propanolol. Dopamine (DA) had a weak stimulatory effect that could be antagonized by the DA1 receptor antagonist, SCH 23390, but not by phentolamine. We conclude that NE and E stimulate hypothalamic IR-rCRH secretion via alpha 1 and alpha 2 receptors. The effect of NE upon IR-rCRH secretion is not apparently mediated by serotonergic or cholinergic interneurons, but is modulated by the inhibitory neurotransmitter, GABA. These data support the idea that the central catecholaminergic systems are excitatory rather than inhibitory upon CRH secretion when acting directly at the hypothalamic level.