Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector

In this Letter, we present the design and performance of the frequency-dependent squeezed vacuum source that will be used for the broadband quantum noise reduction of the Advanced Virgo Plus gravitational-wave detector in the upcoming observation run. The frequency-dependent squeezed field is generated by a phase rotation of a frequency-independent squeezed state through a 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB of generated squeezing, up to 5.6 dB of quantum noise suppression has been measured at high frequency while close to the filter cavity resonance frequency, the intracavity losses limit this value to about 2 dB. Frequency-dependent squeezing is produced with a rotation frequency stability of about 6 Hz rms, which is maintained over the long term. The achieved results fulfill the frequency dependent squeezed vacuum source requirements for Advanced Virgo Plus. With the current squeezing source, considering also the estimated squeezing degradation induced by the interferometer, we expect a reduction of the quantum shot noise and radiation pressure noise of up to 4.5 dB and 2 dB, respectively.

HBV infection is a risk factor for chronic kidney disease: Systematic review and meta-analysis

BACKGROUND

The activity of hepatitis B virus (HBV) as a risk factor for the incidence and progression of chronic kidney disease (CKD) has not been clarified.

AIM

We evaluated the impact of infection with HBV on the risk of CKD in the general population.

MATERIAL AND METHODS

We carried out a systematic review of the published medical literature to assess whether a relationship between hepatitis B infection and an increased risk of CKD in the adult general population occurs. We adopted the random effects model of DerSimonian and Laird to provide a summary estimate of the risk of chronic kidney disease (defined by lowered glomerular filtration rate and/or detectable proteinuria) with HBV infection across the published studies. Meta-regression and stratified analyses were also performed.

RESULTS

We retrieved 33 studies (n = 7,849,849 patients) published in 26 different articles, and separate meta-analyses were performed according to the outcome. Pooling results from cohort studies (11 studies, n = 1,056,645 patients) demonstrated a relationship between positive HBV serologic status and increased incidence of CKD, the summary estimate for adjusted HR with HBV across the surveys, 1.40 (95% CI, 1.16-1.69) (P < .001). Between-study heterogeneity was noted (Q value, 49.5, P < .0001). No relationship between HBV and prevalence of CKD was noted in the subset of cross-sectional studies (10 studies; n = 3,222,545 patients), adjusted OR, 1.04 (95% IC 0.90-1.218; P = .5). Meta-regression analysis reported a relationship between positive HBsAg status and incidence of CKD in the general population (P < .015).

CONCLUSIONS

It appears that exposure to HBV infection seems to be associated with an increased risk of developing CKD in the adult general population. Studies aimed to understand the mechanisms responsible of such association are under way.

HBV infection is a risk factor for chronic kidney disease: Systematic review and meta-analysis

BACKGROUND

The activity of hepatitis B virus (HBV) as a risk factor for the incidence and progression of chronic kidney disease (CKD) has not been clarified.

AIM

We evaluated the impact of infection with HBV on the risk of CKD in the general population.

MATERIAL AND METHODS

We carried out a systematic review of the published medical literature to assess whether a relationship between hepatitis B infection and an increased risk of CKD in the adult general population occurs. We adopted the random effects model of DerSimonian and Laird to provide a summary estimate of the risk of chronic kidney disease (defined by lowered glomerular filtration rate and/or detectable proteinuria) with HBV infection across the published studies. Meta-regression and stratified analyses were also performed.

RESULTS

We retrieved 33 studies (n=7,849,849 patients) published in 26 different articles, and separate meta-analyses were performed according to the outcome. Pooling results from cohort studies (11 studies, n=1,056,645 patients) demonstrated a relationship between positive HBV serologic status and increased incidence of CKD, the summary estimate for adjusted HR with HBV across the surveys, 1.40 (95% CI, 1.16-1.69) (P<.001). Between-study heterogeneity was noted (Q value, 49.5, P<.0001). No relationship between HBV and prevalence of CKD was noted in the subset of cross-sectional studies (10 studies; n=3,222,545 patients), adjusted OR, 1.04 (95% IC 0.90-1.218; P=.5). Meta-regression analysis reported a relationship between positive HBsAg status and incidence of CKD in the general population (P<.015).

CONCLUSIONS

It appears that exposure to HBV infection seems to be associated with an increased risk of developing CKD in the adult general population. Studies aimed to understand the mechanisms responsible of such association are under way.

Transmission of hepatitis C virus infection in hemodialysis: Current concepts

A variety of epidemiological data provides evidence for the occurrence of nosocomial transmission of hepatitis C virus (HCV) infection to hemodialysis (HD) patients. The most important factor implicated in HCV transmission between patients treated in the same dialysis unit is cross-contamination from supplies and surfaces as a result of failure of staff to follow infection control procedures. Parts of the HCV genome are highly variable and lend themselves to fingerprinting of each isolate using nucleic acid testing (NAT) and sequencing. This approach has permitted investigation of possible transmission routes within HD units. A systematic review of molecular virology papers revealed transmission of HCV via internal fluid pathways of the dialysis machines in a minority of reports only. Dialyzer reuse was not identified as a risk factor for HCV acquisition in multicenter databases. No randomized controlled trials exist on the impact of isolation on the risk of transmission of HCV to hemodialysis patients. A Belgian prospective multicenter study showed a reduction from 1.4% to 0% in the annual incidence of seroconversion for HCV without any isolation measures, by implementation of strict infection control procedures designed to prevent transmission of blood-borne pathogens, including HCV. However, an isolation policy for HCV-infected dialysis patients should be considered in dialysis units where nosocomial transmission of HCV persists despite reinforcement and audit of hygienic precautions for hemodialysis. Routine audit precautions (general and for dialysis machines) are recommended on a regular basis within HD units.

Hepatitis C Virus Infection and Diabetes Mellitus in End-Stage Renal Disease: Evidence of a Negative Association

Epidemiological studies have implicated hepatitis C virus (HCV) infection in the pathogenesis of diabetes mellitus (DM) both in the population as a whole and after solid organ transplantation. Whether this association exists in patients with end-stage renal disease (ESRD) undergoing dialysis is unclear. The aim of this study is to investigate the relationship between HCV and DM in a large group (n = 742) of patients with ESRD from Europe and North America. The presence of diabetes was ascertained by using American Diabetes Association guidelines based on fasting glucose measurement and medication history. Presence of HCV infection was assessed by serum testing for anti-HCV antibodies. The prevalence of anti-HCV antibody positive patients was 15% (112/742); the frequency of DM was higher among anti-HCV positive than -HCV negative patients but the difference did not approach statistical significance, 32% (36/112) vs 29.5% (186/630). The frequency of patients with diabetic nephropathy was not higher in anti-HCV positive than -negative patients; 21.4% (24/112) vs 23.3% (147/630), NS. Logistic regression model showed an independent and significant link between anti-HCV seropositive status and raised GPT (P = 0.032), male gender (P = 0.0462), positive history of prior renal transplant (P = 0.0006), and longer time on dialysis (P = 0.00001). In summary, no link between anti-HCV antibody and DM occurred in this ESRD population; there was no association between rate of anti-HCV antibody and diabetic nephropathy.

Lamivudine in the Treatment of HBV-related Liver Disease after Renal Transplantation: An Update

Diminished survival due to hepatitis B has been observed after renal transplantation (RT). Lamivudine, a second-generation nucleoside analogue, has been approved for the treatment of chronic hepatitis B virus (HBV) infection in patients with normal renal function. Numerous clinical experiences with lamivudine after RT have been recently published. Despite numerous shortcomings, all of these reports have shown encouraging results. The rate of clearance of HBV viremia ranged between 67% and 100%, and the frequency of ALT normalization was between 50% and 100% with lamivudine use. Even patients with fibrosing cholestatic hepatitis, a serious form of HBV-related liver disease with ominous course, have been successfully treated with lamivudine. Lamivudine therapy significantly improved the survival of HBsAg positive renal allograft recipients. However, numerous issues concerning the treatment of hepatitis B after RT remain unclear: the optimal time to initiate lamivudine, the appropriate duration of antiviral therapy after RT, and the role for pre-transplantation liver biopsy. Also, the management of lamivudine resistance remains a concern for physicians. Clinical trials are under way.

Hepatitis B Virus Infection in the Dialysis Population: Current Perspectives

One of the major advances in the management of patients on regular dialysis has been the control of the spread of hepatitis B virus (HBV) infection in dialysis units. The rate of HBsAg positive patients on regular dialysis in the developed world is currently low, but outbreaks of HBV continue to occur. The diffusion of HBV in dialysis units in developing countries is higher, although available information is not abundant. There are limited data on the natural history of HBV in the dialysis population; they support a detrimental effect of HBV on survival in dialysis patients. The HBV viral load in HbsAg-positive dialysis patients appears low and stable over time and numerous mechanisms have been posited to explain it. Several assays for detecting HBV DNA in serum are available but they should not be used for purposes of routine screening within dialysis units. The epidemiology and clinical significance of occult HBV infection in the dialysis population needs to be addressed adequately - this remains an area of active research. Recent recommendations for the management of HBsAg chronic carriers on maintenance dialysis have been issued. No controlled trials for the treatment of hepatitis B with either interferon or lamivudine in dialysis patients are currently available.

Interferon Therapy for HCV-Associated Glomerulonephritis: Meta-Analysis of Controlled Trials

Background

A relationship between hepatitis C virus (HCV) infection and chronic glomerulonephritis (GN) has been asserted on the grounds of epidemiological and experimental data. Although this suggests a role for an antiviral approach to HCV-associated GN instead of the more conventional immunosuppressive (or supportive) therapy, the optimal management of HCV-related glomerulonephritis remains controversial.

Objective

To compare antiviral with immunosuppressive therapy for HCV-associated GN.

Design

Meta-analysis of controlled clinical trials (CCTs) of the two treatments (antiviral versus immunosuppressive) of HCV-associated GN.

Methods

We used the fixed or random effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. The rate of proteinuria and serum creatinine decrease after therapy for HCV-associated GN were regarded as the most reliable outcome end-points.

Results

We identified six studies involving 145 unique patients with HCV-associated GN. Pooling of study results demonstrated that proteinuria decreased more commonly after IFN than corticosteroid therapy (OR 1.92 (95% CI, 0.39; 9.57), NS), P-test for heterogeneity, 0.06 (I2=52.9%). In a sensitivity analysis including only CCTs using standard IFN-doses, OR was 3.86 (95% CI, 1.44; 10.33, (P=0.007)), P-test for heterogeneity, 0.18 (I2=35.9%). No improvement of serum creatinine after IFN compared to immunosuppressive therapy was noted (OR, 0.59 (95% CI, 0.21; 1.65), NS), P-test for heterogeneity, 0.76 (I2=0%). Only three CCTs gave information on the rate of proteinuria decrease over follow-up (OR, 5.08 (95% CI, 0.69; 37.31), NS). A few major side effects were noted after IFN administration.

Conclusions

Our meta-analysis indicates that standard IFN-doses were more effective than immunosuppressive therapy in lowering proteinuria of patients with HCV-related glomerulonephritis. However, no significant improvement in serum creatinine was seen by IFN or steroid therapy across the studies. Also, information on proteinuria recurrence after the completion of antiviral therapy was not sufficient. Prospective, randomized trials based on combined antiviral therapy (pegylated IFN plus ribavirin) with adequate dose and follow-up are required to assess the efficacy and safety of antiviral treatment of HCV-associated glomerulonephritis.

Hepatitis C Virus Infection and Post-Transplant Diabetes Mellitus among Renal Transplant Patients: A Meta-Analysis

Objective

To examine the association between HCV infection and the occurrence of post-transplant diabetes mellitus (PTDM) among renal transplant patients.

Design

Meta-analysis of observational studies.

Data Sources

We retrieved studies published in any language by systematically searching Medline, and Embase and by manually examining the references of the original articles, reviews, and monographs retrieved.

Review Methods

We included cohort and case-control studies reporting relative risk estimates and 95% confidence intervals (CIs) for PTDM occurrence with HCV after renal transplantation. Thirteen studies providing information on a total of 30,099 unique patients were included in our meta-analysis.

Results

Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random-effects pooled estimates. The pooled relative risk (RR) for PTDM after RT was 2.73 with a 95% confidence interval (CI) of 1.94; 3.83 (10 studies). In a stratified analysis including only large studies (2 studies), the pooled RR was 1.36 (95% CI, 1.21; 1.54). Egger's regression test showed some evidence of publication bias (p=0.0001), but our sensitivity analysis showed that this issue did not meaningfully change the results.

Conclusions

Our study shows a marked increase of the risk of post-transplant diabetes mellitus in anti-hepatitis C virus-positive renal transplant recipients. The excess risk of death in hepatitis C virus-positive renal transplant recipients may be at least partially attributed to post-transplant diabetes mellitus with its attendant complications.

On the possibility of using X-ray Compton scattering to study magnetoelectrical properties of crystals

The possibility of using X-ray Compton scattering to reveal antisymmetric components of the electron momentum density, as a fingerprint of magnetoelectric sample properties, is investigated experimentally and theoretically by studying the polar ferromagnet GaFeO₃.

This paper discusses the possibility of using Compton scattering – an inelastic X-ray scattering process that yields a projection of the electron momentum density – to probe magnetoelectrical properties. It is shown that an antisymmetric component of the momentum density is a unique fingerprint of such time- and parity-odd physics. It is argued that polar ferromagnets are ideal candidates to demonstrate this phenomenon and the first experimental results are shown, on a single-domain crystal of GaFeO₃. The measured antisymmetric Compton profile is very small (≃ 10⁻⁵ of the symmetric part) and of the same order of magnitude as the statistical errors. Relativistic first-principles simulations of the antisymmetric Compton profile are presented and it is shown that, while the effect is indeed predicted by theory, and scales with the size of the valence spin–orbit interaction, its magnitude is significantly overestimated. The paper outlines some important constraints on the properties of the antisymmetric Compton profile arising from the underlying crystallographic symmetry of the sample.

Diffuse multiple scattering

A new form of diffraction lines similar to Rutherford, Kikuchi and Kossel lines has been identified. They can be used to eliminate the need for sample/source matching in Lonsdale’s triple convergent line method in lattice-parameter determination.

A new form of diffraction lines has been identified, similar to Rutherford, Kikuchi and Kossel lines. This paper highlights some of the properties of these lines and shows how they can be used to eliminate the need for sample/source matching in Lonsdale’s triple convergent line method in lattice-parameter determination.

Antiviral therapy (pegylated interferon and ribavirin) of hepatitis C in dialysis patients: meta-analysis of clinical studies

Information on the antiviral treatment (pegylated interferon plus ribavirin) of chronic infection by hepatitis C virus (HCV) in patients on long-term dialysis is extremely limited. We evaluated the efficacy and safety of combination antiviral therapy (pegylated interferon plus ribavirin) in patients on long-term dialysis with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical studies. The primary outcome was sustained virological response (SVR) (as a measure of efficacy); the secondary outcome was dropout rate (as a measure of tolerability). We used the random-effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. We identified eleven clinical studies (287 unique patients), two of them being controlled clinical trials. The summary estimate for SVR and dropout rate was 0.60 (95% Confidence Intervals, 0.47; 0.71) and 0.18 (95% CI, 0.08; 0.35), respectively; studies being heterogeneous with regard to both the outcomes. Stratified analysis reported a higher SVR rate in controlled trials, 0.86 (95% CI, 0.27; 0.99). The most common sources of dropout were anaemia (11/46 = 23%) and infections (6/46 = 13%). Meta-regression analysis showed a detrimental impact of HCV genotype 1 (P = 0.036) and dropout (P = 0.0001) rate upon the frequency of SVR. Antiviral therapy based on pegylated interferon plus ribavirin for HCV gives encouraging results in terms of efficacy and safety among patients on long-term dialysis; such approach should be considered the current standard of care for HCV-infected individuals on regular dialysis.

Hepatitis C virus infection and glomerular disease

The association between hepatitis C virus (HCV) infection and chronic kidney disease (CKD) is well established and remains an area of intense research. HCV infection is associated with a large spectrum of histo-pathological lesions in both native and transplanted kidneys. The frequency of kidney damage in HCV-infected patients appears low even if is not fully detailed. The most frequent HCV-associated renal lesion is type I membrano-proliferative glomerulonephritis, usually in the context of type II mixed cryoglobulinemia. Various approaches have been tried for the treatment of HCV-related glomerulonephritis, including immunosuppressive therapy (corticosteroids and cytotoxic agents), plasma exchange and antiviral agents. Antiviral treatment of HCV-associated glomerulonephritis has shown encouraging results. Immunosuppressive therapy is particularly recommended for cryoglobulinemic kidney disease. Two distinct approaches should be considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis according to the level of proteinuria and kidney failure. Some evidence on rituximab therapy for HCV-related cryoglobulinemic glomerulonephritis exists but several questions related to its use need to be addressed.

Meta-analysis of observational studies: hepatitis C and survival after renal transplant

Recent evidence has shown that anti-HCV-positive serologic status is significantly linked to lower patient and graft survival after renal transplant, but conflicting results have been given on this point. The aim of this study was to conduct a systematic review of the published medical literature concerning the impact of HCV infection on all-cause mortality and graft loss after RT. The relative risk of all-cause mortality and graft loss was regarded as the most reliable outcome end-point. Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random-effect pooled estimates for mortality and graft loss with HCV across the published studies. We identified eighteen observational studies involving 133 530 unique renal transplant recipients. The summary estimate for adjusted relative risk (aRR) of all-cause mortality was 1.85 with a 95% confidence interval (CI) of 1.49; 2.31 (P < 0.0001); heterogeneity statistics, Ri = 0.87 (P-value by Q-test = 0.001). The overall estimate for adjusted RR of all-cause graft loss was 1.76 (95% CI, 1.46; 2.11) (P < 0.0001), heterogeneity statistics, Ri = 0.65 (P-value by Q-test = 0.001). Stratified analysis did not change meaningfully these results. Meta-regression showed that living donor rate had a favourable influence on patient (P = 0.031) and graft survival (P = 0.01), whilst diabetes mellitus having a detrimental role on patient survival (P = 0.001). This meta-analysis of observational studies supports the notion that HCV-positive patients after RT have an increased risk of mortality and graft loss. Further studies are in progress to understand better the mechanisms underlying the relationship between HCV and mortality or graft dysfunction after renal transplant.

Recent advances in the management of hepato-renal syndrome (HRS)

Hepato-renal syndrome (HRS) is a functional renal failure complicating end-stage liver disease. HRS is characterized by marked arterial vasodilation (mainly of the splanchnic bed) and severe renal vasoconstriction. HRS is classified into 2 types: type I HRS shows a rapid and progressive decline in renal function with a very poor prognosis (median survival of about 2 weeks); HRS type 2 has a more stable renal failure, with a median survival of about 6 months. The management of HRS is still a big challenge. The definitive therapy for HRS is liver transplantation (LT); however, the survival rate of HRS patients is poor, and important organ shortage exists. Various approaches have been used for HRS treatment including vasoconstrictor therapy. Recent evidence has shown that vasoconstrictor agents are effective and serve as a bridge to LT; the rationale for vasoconstrictors is to counteract the splanchnic arterial vasodilation and increase the effective arterial blood volume. Thus, renal perfusion and glomerular filtration rates improve. Terlipressin, a V1 vasopressin agonist, has been used frequently. A recent meta-analysis of clinical trials showed that the pooled rate of patients who reversed HRS after terlipressin therapy was 0.52 (95% CI, 0.42; 0.61; P = 0.0001, /2 = 24.6%). The pooled Odds Ratio (OR) for mortality rate in HRS patients who were not responders to terlipressin versus responders was 5.746 (95% CI, 1.5; 21.9; P = 0.0005). Prospective, controlled clinical trials are in progress to address the impact of vasoconstrictor use on survival in HRS patients. Alternative therapies such as transjugular intrahepatic portosystemic shunts (TIPS) and extracorporeal albumin dialysis (ECAD) have given encouraging results but experience is extremely limited.

Lamivudine treatment for hepatitis B in dialysis population : case reports and literature review

It is well known that chronic hepatitis B plays a detrimental role on survival in patients on long-term dialysis and after kidney transplantation. The advent of nucleos(t)ide analogues offers the opportunity to change the natural history of hepatitis B in patients with chronic kidney disease. We report our experience on lamivudine use in two patients with HBV-related liver disease on long-term dialysis. At the beginning, both the patients were HBsAg positive and HBeAg positive with high viral load; after long-term lamivudine therapy, clearance of HBV viremia from serum was observed in both. Raised aminotransferase levels fell into the normal range and one patient experienced clearance of HBsAg by anti-HBV therapy. Tolerance to lamivudine was satisfactory and lamivudine resistance was not detected. Information on antiviral therapy with lamivudine in HBsAg positive patients on regular dialysis is extremely limited; we identified by an extensive review of the literature five studies with a total of 38 unique patients, most of them being renal transplant candidates. Lamivudine proved to be effective as the clearance of HBV viraemia from serum ranged between 56% and 100% ; the clearance of HBeAg from serum was less evident (between 37.5% and 100%). No significant side-effects due to lamivudine were observed and emergence of lamivudine-resistant strains was observed in two (5%) patients. Only a minority of patients experienced HBsAg loss (13%). We conclude that anti-HBV treatment with a nucleoside analogue such as lamivudine gives satisfactory results in some patients on long-term dialysis. Clinical trials are in progress to assess efficacy and safety of last-generation nucleos(t)ide analogues for anti-HBV therapy in dialysis population.

MnSb2O6: a polar magnet with a chiral crystal structure

Structural and magnetic chiralities are found to coexist in a small group of materials in which they produce intriguing phenomenologies such as the recently discovered Skyrmion phases. Here, we describe a previously unknown manifestation of this interplay in MnSb(2)O(6), a trigonal oxide with a chiral crystal structure. Unlike all other known cases, the MnSb(2)O(6) magnetic structure is based on corotating cycloids rather than helices. The coupling to the structural chirality is provided by a magnetic axial vector, related to the so-called vector chirality. We show that this unique arrangement is the magnetic ground state of the symmetric-exchange Hamiltonian, based on ab initio theoretical calculations of the Heisenberg exchange interactions, and is stabilized by out-of-plane anisotropy. MnSb(2)O(6) is predicted to be multiferroic with a unique ferroelectric switching mechanism.

Interferon therapy of acute hepatitis C in dialysis patients: meta-analysis

The efficacy and safety of antiviral therapy in patients with acute hepatitis C on long-term dialysis remains unclear, although a number of small clinical studies have been published addressing this issue. We evaluated the efficacy and safety of interferon therapy in chronic dialysis patients with acute hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical studies. The primary outcome was sustained virological response (SVR, as a measure of efficacy); the secondary outcome was dropout rate (as a measure of tolerability). We used the random effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. We identified eight clinical studies (173 unique patients), three (37.5%) being controlled clinical trials (CCTs). Among CCTs, the viral response was much more common in study (patients on antiviral therapy) than control (patients who did not receive therapy) groups; the pooled odds ratio of SVR being 27.06, 95% Confidence Intervals (95% CI), 9.26; 79.1 (P = 0.00001). No difference in the dropout rate between study and control patients was shown, odds ratio = 0.920 (95% CI, 0.367; 1.92), NS. Pooling all study results (n = 8 studies) demonstrated that the summary estimate for SVR and dropout rate was 58% (95% CI, 38; 77) and 9% (95% CI, 4; 14), respectively. The most frequent side-effects requiring interruption of the treatment were flu-like symptoms (n = 4, 18%), followed by haematological changes and loss to follow-up. A strong relationship between increasing age and reported dropout rate was recognized (P = 0.001). The studies were heterogeneous with regard to SVR but not to dropout rate. Our meta-analysis of CCTs showed that the viral response after antiviral therapy was more common than the spontaneous viral clearance in dialysis patients with acute hepatitis C. Pooled analysis demonstrated that IFN-based therapy of acute hepatitis C in dialysis populations gives SVR in around one half of patients. These results support IFN-based therapy for acute hepatitis C in patients on maintenance dialysis.

Impact of hepatitis C on survival in dialysis patients: a link with cardiovascular mortality?

Recent evidence has been accumulated showing that anti-HCV-positive serologic status is significantly associated with lower survival in dialysis populations, but the mechanisms underlying this negative relationship are still unclear. The aim of this study was to conduct a systematic review of the published medical literature concerning the impact of hepatitis C virus (HCV) infection on all-cause and disease-specific mortality of patients on regular dialysis. The relative risk of all-cause, cardiovascular and liver disease-related mortality was regarded as the most reliable outcome end-point. Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random effect pooled estimates for mortality with HCV across the published studies. We identified fourteen observational studies involving 145 608 unique patients on long-term dialysis. Pooling of study results demonstrated that anti-HCV antibody was an independent and significant risk factor for death in patients on maintenance dialysis. The summary estimate for adjusted relative risk (all-cause mortality) was 1.35 with a 95% confidence interval (CI) of 1.25-1.47. Stratified analysis showed that the adjusted RR for liver disease-related death was 3.82 (95% CI, 1.92; 7.61); heterogeneity statistics, R(i) = 0.58 (P-value by Q-test = 0.087). The adjusted RR for cardiovascular mortality was 1.26 (95% CI, 1.10; 1.45); no heterogeneity was found (NS). This meta-analysis of observational studies indicates that anti-HCV-positive patients on dialysis have an increased risk of either liver or cardiovascular disease-related mortality compared with anti-HCV-negative patients. Further studies are in progress to understand better the link between HCV and cardiovascular risk among patients on maintenance dialysis.

Hepatitis C virus and the immunological response to hepatitis B virus vaccine in dialysis patients: meta-analysis of clinical studies

It is well known that the seroconversion rate of patients following hepatitis B virus (HBV) vaccination is lower in uraemic than healthy subjects. A variety of inherited or acquired factors have been implicated in this diminished response, and the high prevalence of hepatitis C virus (HCV) infection among patients on maintenance dialysis has been suggested to play a role. However, the impact of HCV on the immune response to HB vaccine in patients receiving long-term dialysis is not entirely understood. Here, we evaluate the influence of HCV infection on the immunological response to HBV vaccine in dialysis population by performing a systematic review of the literature with a meta-analysis of clinical studies.We used the random-effects model of DerSimonian and Laird with heterogeneity and sensitivity analyses. The end-point of interest was the rate of patients showing seroprotective anti-hepatitis B titres at completion of HBV vaccine schedule among HCV-positive versus HCV-negative patients on chronic dialysis. We identified eight studies involving 520 unique patients on long-term dialysis. Aggregation of study results did not show a significant decrease in response rates among HCV-infected versus noninfected patients [pooled odds ratio = 0.621 (95% CI, 0.285; 1.353)]. The P-value was 0.007 for our test of study heterogeneity. Stratified analysis in various subgroups of interest did not meaningfully change our results. Our meta-analysis showed no association between immunological response to hepatitis B vaccine and HCV infection in individuals on long-term dialysis. These results support the use of recombinant vaccine against hepatitis B in patients on regular dialysis with HCV infection.

Intradermal vs intramuscular vaccine against hepatitis B infection in dialysis patients: a meta-analysis of randomized trials

Chronic dialysis patients are at risk of contracting hepatitis B virus infection and have a diminished immune response to hepatitis B virus vaccine. Recent reports support intradermal administration of hepatitis B virus vaccine in patients on regular dialysis but the efficacy and safety of this approach remain unclear. We conducted a meta-analysis of randomized, controlled clinical trials to compare seroprotection achieved by intradermal vs intramuscular hepatitis B vaccine, in patients on maintenance dialysis. Meta-analysis of data from 718 adults (14 trials) on long-term dialysis demonstrated that intramuscular hepatitis B vaccination was less likely to achieve seroprotection than intradermal vaccination, the pooled odds ratio was 0.454 (95% CI, 0.3; 0.67), P = 0.001. The test of study heterogeneity was not significant. This difference did not persist during follow-up (6-60 months after completing vaccine schedule), the pooled odds ratio being 0.718 (95% CI, 0.36; 1.47), NS. Some evidence of significant heterogeneity including publication bias was present but stratified analysis in various subgroups showed that this issue did not meaningfully change our results. Intradermal hepatitis B vaccine was safe and well tolerated. We conclude that intradermal hepatitis B vaccine induces a superior response rate compared to intramuscular route at completion of vaccine cycle, despite a lower vaccine dose. No significant advantage was found over longer follow-up. It remains unclear whether the higher seroprotection rate achieved with intradermal route translates into a lower frequency of de novo hepatitis B among patients on maintenance dialysis.

Femtoscale Magnetically Induced Lattice Distortions in Multiferroic TbMnO3

Magneto-electric multiferroics exemplified by TbMnO3 possess both magnetic and ferroelectric long-range order. The magnetic order is mostly understood, whereas the nature of the ferroelectricity has remained more elusive. Competing models proposed to explain the ferroelectricity are associated respectively with charge transfer and ionic displacements. Exploiting the magneto-electric coupling, we used an electric field to produce a single magnetic domain state, and a magnetic field to induce ionic displacements. Under these conditions, interference between charge and magnetic x-ray scattering arose, encoding the amplitude and phase of the displacements. When combined with a theoretical analysis, our data allow us to resolve the ionic displacements at the femtoscale, and show that such displacements make a substantial contribution to the zero-field ferroelectric moment.

Combined antiviral therapy of hepatitis C virus in dialysis patients: meta-analysis of clinical trials

The efficacy and safety of combined interferon (IFN) plus ribavirin in patients on long-term dialysis and chronic hepatitis C remains unclear, although a number of small clinical trials have addressed this issue. We evaluated the efficacy and safety of combination antiviral therapy (conventional or pegylated interferon plus ribavirin) in dialysis patients with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcome was sustained virological response (SVR) (as a measure of efficacy); the secondary outcome was drop-out rate (as a measure of tolerability). We used the random effects model of Der Simonian and Laird, with heterogeneity and sensitivity analyses. We identified 10 clinical studies (151 unique patients), one (10%) of which was a controlled clinical trial. Most (97.4%) patients were on long-term haemodialysis. The summary estimate for SVR and drop-out rate was 56% [95% Confidence Intervals (95% CI) 28-84] and 25% (95% CI, 10-40), respectively. The most frequent side effects requiring interruption of treatment were anaemia (26%) and heart failure (9%). These results occurred irrespective of type of interferon (conventional or peg-IFN, peg-IFNalfa-2a or alfa-2b), trial design (controlled or cohort study), or clinical characteristics of patients (naïve, nonresponders or relapsers). The studies were heterogeneous with regard to SVR and drop-out rate. Combination antiviral therapy (interferon plus ribavirin) gives encouraging results in terms of efficacy and safety among dialysis patients even if the limited number of patients enrolled in our meta-analysis hampers definitive conclusions.

Meta-analysis: the impact of diabetes mellitus on the immunological response to hepatitis B virus vaccine in dialysis patients

BACKGROUND

Patients on maintenance dialysis typically show a suboptimal immune response to hepatitis B virus vaccine compared with the non-uraemic population. A variety of inherited or acquired factors have been implicated in this diminished response. It is well known that patients with diabetes mellitus have a compromised immune system, and diabetic nephropathy is an important cause of chronic kidney disease. However, the impact of diabetes mellitus on the immune response to HBV vaccine in patients receiving long-term dialysis remains unclear.

AIM

To evaluate the influence of diabetes mellitus on the immune response to HBV vaccine in dialysis population by performing a systematic review of the literature with a meta-analysis of clinical studies.

METHODS

We used the random effects model of DerSimonian and Laird with heterogeneity and sensitivity analyses. The end-point of interest was the rate of patients showing seroprotective antibody against hepatitis B surface antigen at completion of vaccine schedule in the diabetic vs. the nondiabetic dialysis individuals.

RESULTS

We identified 12 studies involving 1002 unique patients on long-term dialysis. Aggregation of study results showed a significant decrease in response rates among the diabetic vs. the nondiabetic patients [pooled odds ratio=0.52 (95% CI 0.38-0.71)]. The P-value was 0.29 for our test of study heterogeneity. Stratified analysis in various subgroups of interest did not meaningfully change our results.

CONCLUSIONS

Our meta-analysis showed a clear association between diabetes mellitus and impaired response to hepatitis B virus vaccine in individuals on long-term dialysis. Such a relationship is biologically plausible. Vaccination schedules with adapted vaccine doses and frequent serum testing for loss of immunity against hepatitis B virus should be considered in patients on maintenance dialysis with diabetes mellitus.

Hepatitis B and hepatitis C virus and chronic kidney disease

The most common cause of liver disease in patients with chronic kidney disease (CKD) remains infection by hepatitis B virus (HBV) and/or hepatitis C virus (HCV). The adverse effects of HBV and/or HCV infections upon survival in patients with CKD have been repeatedly confirmed. An excess risk of death in HBsAg positive or anti-HCV antibody-positive patients may be at least partially attributed to chronic liver disease with its attendant complications. A negative impact of HCV infection on survival after renal transplantation has been linked to extrahepatic complications, including chronic glomerulonephritis, sepsis, chronic allograft nephropathy, post-transplantation diabetes mellitus, and abnormal metabolism of calcineurin-inhibitors. Transmission of HCV infection by grafts from HCV-infected donors has been unequivocally demonstrated. Registry analyses suggest that recipients of kidneys from anti-HCV antibody positive donors are at increased risk of mortality. Renal grafts from HCV-infected donors should be restricted to viremic anti-HCV positive recipients. Several drugs have been recently licensed for therapy of HBV infection but availabledata in patients with CKD is mostly limited to experience with lamivudine. The standard of care for hepatitis C infection in patients on regular dialysis is monotherapy with conventional interferon, according to recent guidelines. Only dire circumstances justify interferon use after renal transplantation.

Meta-analysis: levamisole improves the immune response to hepatitis B vaccine in dialysis patients

BACKGROUND

Patients undergoing maintenance dialysis often fail to mount protective antibodies to hepatitis B virus surface antigen (HBsAg) following vaccination against hepatitis B virus (HBV). Some authors have suggested that levamisole improves immune response to HBV vaccine in dialysis population. However, consistent information on this issue does not exist.

AIM

To evaluate efficacy and safety of levamisole as adjuvant to hepatitis B virus (HBV) vaccine in dialysis patients by performing a systematic review of the literature with a meta-analysis of clinical trials.

METHODS

We used the random-effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. Only trials comparing the seroresponse rate in study subjects (levamisole plus HBV vaccine) vs. controls (HBV vaccine alone) were included. The end point of interest was the rate of patients showing seroprotective anti-hepatitis B titres at completion of HBV vaccine schedule in study vs. control groups.

RESULTS

We identified four studies involving 328 unique patients on regular dialysis. Only prospective, randomized clinical trials (RCTs) were included. Pooling of study results showed a significant increase in response rates among study (levamisole plus HBV vaccine) vs. control (HBV vaccine alone) patients; the pooled Odds Ratio was 2.432 (95% Confidence Intervals, 1.34; 4.403), P = 0.002. No study heterogeneity was found. These results did not change in various subgroups of interest.

CONCLUSIONS

Our meta-analysis showed that levamisole significantly improves immune response to hepatitis B vaccine in dialysis population. The limited number of patients precluded more conclusions.

Meta-analysis: levamisole improves the immune response to hepatitis B vaccine in dialysis patients

BACKGROUND

Patients undergoing maintenance dialysis often fail to mount protective antibodies to hepatitis B virus surface antigen (HBsAg) following vaccination against hepatitis B virus (HBV). Some authors have suggested that levamisole improves immune response to HBV vaccine in dialysis population. However, consistent information on this issue does not exist.

AIM

To evaluate efficacy and safety of levamisole as adjuvant to hepatitis B virus (HBV) vaccine in dialysis patients by performing a systematic review of the literature with a meta-analysis of clinical trials.

METHODS

We used the random-effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. Only trials comparing the seroresponse rate in study subjects (levamisole plus HBV vaccine) vs. controls (HBV vaccine alone) were included. The end point of interest was the rate of patients showing seroprotective anti-hepatitis B titres at completion of HBV vaccine schedule in study vs. control groups.

RESULTS

We identified four studies involving 328 unique patients on regular dialysis. Only prospective, randomized clinical trials (RCTs) were included. Pooling of study results showed a significant increase in response rates among study (levamisole plus HBV vaccine) vs. control (HBV vaccine alone) patients; the pooled Odds Ratio was 2.432 (95% Confidence Intervals, 1.34; 4.403), P = 0.002. No study heterogeneity was found. These results did not change in various subgroups of interest.

CONCLUSIONS

Our meta-analysis showed that levamisole significantly improves immune response to hepatitis B vaccine in dialysis population. The limited number of patients precluded more conclusions.

Circularly polarized X rays as a probe of noncollinear magnetic order in multiferroic TbMnO3

Nonresonant x-ray magnetic scattering has been used to study the magnetic structure of multiferroic TbMnO3 in its ferroelectric phase. Circularly polarized x rays were combined with full polarization analysis of the scattered beam to reveal important new information on the magnetic structure of this canonical multiferroic. An applied electric field is shown to create essentially a single magnetic domain state in which the cycloidal order on the Mn sublattice rotates either clockwise or anticlockwise depending on the sign of the field. It is demonstrated how this technique provides sensitivity to the absolute sense of rotation of the Mn moments and to components of the ordering on the Tb sublattice and phase shifts that earlier neutron diffraction experiments could not resolve.

Impact of hemodialysis therapy on hepatitis C virus infection: a deeper insight

Hepatitis C Virus (HCV) infection remains prevalent in patients receiving regular dialysis all over the world. The adverse impact of anti-HCV serologic status on mortality in the dialysis population has been documented. Antiviral therapy for hepatitis C in chronic kidney disease (CKD) patients, including the dialysis population, is still unsatisfactory. Several findings support a different course of HCV in dialysis patients versus the non-uremic population. The HCV viral load appears lower in hemodialysis patients with HCV despite the immune compromise caused by chronic uremia; the histologic abnormalities seem milder, and a severe clinical course of chronic hepatitis C is unusual in most hemodialysis (HD) patients. It appears that the HD procedure per se can preserve patients from an aggressive course of HCV by reducing the viral load (HCV RNA). The mechanisms by which the HD procedure lowers HCV viremia remain largely speculative: the passage of viral particles into the dialysate, the trapping of the virus on the surface of the dialyzer membrane, and an indirect host-mediated mechanism have been cited. The latter hypothesis implicates the production of interferon-alpha, hepatocyte growth factor, or other cytokines provided with antiviral activities during the hemodialysis sessions. Clinical trials aimed at clarifying this issue are under way.