Interleukin 28B-related polymorphisms: A pathway for understanding hepatitis C virus infection?

AIM:To analyze the role of rs12979860 and rs8099917polymorphisms in hepatitis C virus(HCV)genotype 1infection of Brazilians.METHODS:A total of 145 adult patients diagnosed with genotype 1 chronic hepatitis C(CHC)who had completed a 48-wk regimen of pegylated-interferonα-2a or-2b plus ribavirin combination therapy were recruited from six large urban healthcare centers and199 healthy blood donors(controls)from a single site between January 2010 and January 2012.Data on the patients’response to treatment was collected.Polymerase chain reaction-restriction fragment length polymorphism genotyping of the interleukin(IL)28B gene fragment encompassing the single nucleotide polymorphisms(SNPs)rs12979860(C/T)and rs8099917(T/G)was carried out for 79 of the CHC patients and 199 of the controls.Bi-directional amplicon sequencing of the two SNPs was carried out for the remaining 66 CHC patients.RESULTS:SNP rs12979860 genotyping was successful in 99.5%of the controls and 97.2%of the CHC patients,whereas the SNP rs8099917 genotyping was successful in 95.5%of the controls and 100%of the CHC patients.The genotype and allele distributions for both rs12979860 and rs8099917 were significantly different between the control and CHC patient groups,with significantly higher genotype frequencies of CC and TT in the controls(P=0.037 and 0.046,respectively)and of TT and GG in the CHC patients(P=0.0009and 0.0001,respectively).Analysis of the CHC patients who achieved sustained virological response(SVR)to treatment(n=55)indicated that the rs12979860 C allele and CC genotype were predictors of SVR(P=0.02).No significant correlation was found between rs8099917 genotypes and treatment response,but carriers of the T allele showed significantly higher rates of SVR(P=0.02).Linkage disequilibrium analysis of the group that achieved SVR showed a significant association between rs12979860 and rs8099917(P=0.07).CONCLUSION:The higher allele frequency of rs12979860 C and rs8099917 T observed in non-HCVinfected individuals may indicate a potential pro     

Hippocampal molecular mechanisms involved in the enhancement of fear extinction caused by exposure to novelty

Exposure to a novel environment enhances the extinction of contextual fear. This has been explained by tagging of the hippocampal synapses used in extinction, followed by capture of proteins from the synapses that process novelty. The effect is blocked by the inhibition of hippocampal protein synthesis following the novelty or the extinction. Here, we show that it can also be blocked by the postextinction or postnovelty intrahippocampal infusion of the NMDA receptor antagonist 2-amino-5-phosphono pentanoic acid; the inhibitor of calcium/calmodulin-dependent protein kinase II (CaMKII), autocamtide-2–related inhibitory peptide; or the blocker of L-voltage–dependent calcium channels (L-VDCCs), nifedipine. Inhibition of proteasomal protein degradation by β-lactacystin has no effect of its own on extinction or on the influence of novelty thereon but blocks the inhibitory effects of all the other substances except that of rapamycin on extinction, suggesting that their action depends on concomitant synaptic protein turnover. Thus, the tagging-and-capture mechanism through which novelty enhances fear extinction involves more molecular processes than hitherto thought: NMDA receptors, L-VDCCs, CaMKII, and synaptic protein turnover.Frey and Morris (1, 2) and their collaborators (3–7) proposed a mechanism whereby relatively “weak” hippocampal long-term potentiation (LTP) or long-term depression (LTD) lasting only a few minutes can nevertheless “tag” the synapses involved with proteins synthesized ad hoc, so that other plasticity-related proteins (PRPs) produced at other sets of synapses by other LTPs or LTDs can be captured by the tagged synapses and strengthen their activity to “long” LTPs or LTDs lasting hours or days (8). LTDs and LTPs can “cross”-tag each other; that is, LTDs can enhance both LTDs and LTPs, and vice versa (6, 8). Because many learned behaviors rely on hippocampal LTP or LTD (7–9), among them the processing of novelty (9, 10) and the making of extinction (11–13), interactions between consecutive learnings can also be explained by the “tagging-and-capture” hypothesis (9, 10, 13), whose application to behavior became known as “behavioral tagging and capture” (5, 7, 9, 13). Typically, exposure to a novel environment [e.g., a nonanxiogenic 50 × 50 × 40-cm open field (OF) (5, 7, 9, 10, 14)] is interpolated before testing for another task, which becomes enhanced (4–10, 13). The usual reaction to novelty is orienting and exploration (14), followed by habituation of this response (14–16). Habituation is perhaps the simplest form of learning, and it consists of inhibition of the orienting/exploratory response (14, 16).We recently showed that the brief exposure of rats to a novel environment (the OF) within a limited time window enhances the extinction of contextual fear conditioning (CFC) through a mechanism of synaptic tagging and capture (13), which is a previously unidentified example of behavioral tagging of inhibitory learning. Fear extinction is most probably due to LTD in the hippocampus (11, 12), although the possibility that it may also involve LTP is not discarded (13). The enhancement of extinction by novelty probably relies on the habituation to the novel environment, which is also probably due to LTD (15, 16). The enhancement of extinction by the exposure to novelty depends on hippocampal gene expression and ribosomal protein synthesis following extinction training and on both ribosomal and nonribosomal protein synthesis caused by the novel experience (13). Nonribosomal protein synthesis that can be blocked by rapamycin is believed to be dendritic (13, 17), so it would be strategically located for tagging-and-capture processes, but it has not been studied in synaptic tagging to date (3–8) or in other forms of behavioral tagging (7–10). As occurs with the interactions between LTPs and/or LTDs (4), the enhancement of extinction by novelty relies on hippocampal but not amygdalar processes (13).Recent findings indicate that several hippocampal processes related to learning and memory, such as the reconsolidation of spatial learning, are highly dependent on NMDA glutamate receptors, calcium/calmodulin protein kinase II (CaMKII), and long-term voltage channel blockers (L-VDCCs), which, in turn, rely on the proteasomal degradation of proteins (18). Here, we study the effects of an NMDA blocker, 2-amino-5-phosphono pentanoic acid (AP5); the L-VDCC blocker nifedipine (Nife); a CaMKII inhibitor, the autocamtide-2–related inhibitory peptide (AIP); and the irreversible proteasome blocker β-lactacystin (12, 13) on the interaction between novelty and extinction (11). As will be seen, we found that both the setting up of tags by extinction and the presumable production of PRPs by the processing of novelty are dependent on NMDA receptors, CaMKII, and L-VDCCs. This endorses and expands the hypothesis that the novelty–extinction interaction relies on synaptic tagging and capture (13).     

Staging Fibrosis in Chronic Viral Hepatitis

Staging fibrosis accurately has always been a challenge in viral hepatitis and other liver diseases. Liver biopsy is an imperfect gold standard due to its intra and interobserver agreement limitations and additional characteristics such as its safety and cost. Hence, non-invasive tests have been developed to stage liver fibrosis. In addition to serological biomarkers, physical tests with reasonable accuracy are available and adopted in the daily clinic regarding viral hepatitis fibrosis staging. In this review, we discuss the published data regarding the staging of liver fibrosis in chronic hepatitis B and C, emphasizing non-invasive markers of fibrosis, both serological and physical. Moreover, we also discuss a persistent central gap, the evaluation of liver fibrosis after HCV cure.     

Use of phytotherapy in dentistry

Over the past decade, interest in drugs derived from medicinal plants has markedly increased. This study was aimed at a literature review focusing on studies investigating herbal drugs and other natural products, as well as their therapeutic application, side effects and possible drug interactions. Few studies were found to support their rational use in dentistry. Since there is an increasing use of phytotherapeutic agents in dentistry, further studies are needed to evaluate their safety and effectiveness for clinical use.     

Effects of polyunsaturated fatty acids (PUFAs) in the treatment of experimental chronic renal failure

Purpose

A diet with polyunsaturated fatty acid (PUFA) supplementation has been reported to reduce renal and cardiac diseases. This study sought to elucidate whether PUFAs derived from plant or marine oils could have beneficial effects on the progression of experimental chronic renal failure (CRF).

Methods

Experimental CRF was achieved by a 5/6 nephrectomy model. Male Wistar rats were divided into groups and given daily supplements of fish oil (group FO), flaxseed oil (group FXO), or soybean oil (control?Cgroup SO) for 30?days. Serum creatinine (sCr), 24-h proteinuria, total cholesterol, triglycerides, and creatinine clearance (CLcr) were measured at day 0 and 30?days after surgery when the rats were euthanized for histological analysis of the remnant kidney.

Results

After 30?days, we observed lower levels of sCr in the groups supplemented with PUFA when compared with the control group (FO: 0.92?±?0.13; FXO: 1.06?±?0.28; SO: 1.32?±?0.47?mg/dL) and significantly slower variations of sCr (??sCr) in the groups treated with PUFAs (FO?=?0.35?±?0.16; FXO?=?0.47?±?0.31; OS?=?0.72?±?0.43; mg/dL, P?=?0.041). Similarly, the CLcr of both of the groups that received PUFAs was significantly slower than the rats in the control group (FO: 0.45?±?0.15; FXO: 0.60?±?0.09; SO: 0.28?±?0.06?mL/min/day; P?=?0.01). The rats that received PUFA supplements also presented significantly less histological lesions compared with the control group.

Conclusions

These results suggest a beneficial effect of dietary supplementation with flaxseed or fish oil in rats with CRF.