Clearance Phase Research Articles

Characterization of bone perfusion by dynamic contrast-enhanced magnetic resonance imaging and positron emission tomography in the Dunkin-Hartley guinea pig model of advanced osteoarthritis.

This study characterizes changes in subchondral bone circulation in OA and examines relationships to bone structure and cartilage degeneration in Dunkin-Hartley guinea pigs. We have used dynamic contrast-enhanced MRI (DCE-MRI) and PET, with pharmacokinetic modeling, to characterize subchondral bone perfusion. Assessments are made of perfusion kinetics and vascular permeability by MRI, and blood volume and flow, and radionuclide incorporation into bone, by PET. These parameters are compared to cartilage lesion severity and bone histomorphometry. Assessments of intraosseous thrombi are made morphologically. Prolonged signal enhancement during the clearance phase of MRI correlated with OA severity and suggested venous stasis. Vascular permeability was not increased indicating that transvascular migration of contrast agent was not responsible for signal enhancement. Intraosseous thrombi were not observed. Decreased perfusion associated with severe OA was confirmed by PET and was associated with reduced radionuclide incorporation and osteoporosis. MRI and PET can be used to characterize kinetic parameters of circulation in OA and correlate them with subchondral bone metabolism of interest to the pathophysiology of OA. The significance of these observations may lie in alterations induced in the expression of cytokines by OA osteoblasts that are related to bone remodeling and cartilage breakdown.

Quantitative hepatitis B core antibody levels in the natural history of hepatitis B virus infection

We previously demonstrated that pretreatment quantitative anti–hepatitis B core protein (qAnti-HBc) levels can predict the treatment response for both interferon and nucleoside analogue therapy, but the characteristics of qAnti-HBc during chronic hepatitis B virus (HBV) infection remain poorly understood. To understand this issue, the qAnti-HBc levels were evaluated in individuals with past HBV infection, occult HBV infection and chronic HBV infection in the immune tolerance phase, immune clearance phase, low-replicative phase and hepatitis B e antigen (HBeAg)-negative hepatitis phase. Individuals with hepatitis B surface antigen (n = 598, 3.74 ± 0.90 log10 IU/mL) had significantly higher (p < 0.001, approximately 1000-fold) serum qAnti-HBc levels than those who had occult HBV, and serum qAnti-HBc levels were significantly higher in the occult HBV group than in the past HBV infection group (p < 0.001). qAnti-HBc levels were positively correlated with alanine aminotransferase levels (R = 0.663, p < 0.001), and subjects with an abnormal alanine aminotransferase level had a higher qAnti-HBc level (p < 0.001). Serum qAnti-HBc level varied in different phases of HBV infection, as determined by host immune status. Serum qAnti-HBc level is strongly associated with hepatitis activity in subjects with chronic HBV infection.

乙型肝炎相关性肝衰竭患者HBV DNA低水平复制及特异性抗体表达的临床意义

Objective To investigate the influential factors and clinical significance of low- level hepatitis B virus ( HBV) DNA replication and specific antibody expression in patients with HBV- related liver failure. Methods A retrospective analysis was performed on the medical records of 391 patients with HBV- related liver failure and 394 patients with chronic hepatitis B ( CHB) hospitalized in the Tianjin Second People's Hospital from June 2008 to December 2013. The HBV DNA level was compared between patients with HBV- related liver failure and those with CHB, and the influential factors were analyzed. According to the expression of HBV serum markers ( HBV- Ms) , patients with liver failure were divided into specific antibody- positive group ( positive for anti- HBs, anti- HBe or anti- HBc) and specific antibody- negative group ( negative for anti- HBs, anti- HBe or anti- HBc) . The changes in HBV DNA level and survival were compared between the two groups. Between- group comparison was made by independent- samples t test or Mann- Whitney rank sum test, and comparison of enumeration data was made by chi- square test. Results The patients with HBV- related liver failure had a significantly lower HBV DNA level than the CHB patients ( Z =- 16. 469, P < 0. 05) . The levels of HBV DNA in HBeAg- positive and- negative patients with liver failure were significantly lower than those in patients with CHB ( Z1=- 11. 665, P < 0. 05; Z2=- 12. 853, P < 0. 05) . Of the391 patients with HBV- related liver failure, 29 ( 7. 42%) were specific antibody- positive, and 25 ( 86. 21%) of them died; 362 ( 92. 58%) were specific antibody-negative, and 157 ( 43.37%) of them died. There was a significant difference in mortality between the specific antibody- positive and specific antibody- negative groups ( P < 0. 05) . The specific antibody- positive group had a significantly lower HBV DNA level than the specific antibody- negative group ( Z =- 3. 594, P < 0. 05) . For either group, the HBV DNA level was significantly lower in HBeAg- negative patients than in HBeAg- positive patients ( Z = 7. 427 or 7. 513, P < 0. 05) . Conclusion HBV M expression and the body's immune status play a role in the progression of HBV- related liver failure. HBV DNA replication is at a low level in the immune clearance phase. Being positive for anti- HBs, anti- HBe, and anti- HBc suggest a super immune response to HBV, leading to rapid progression of disease and high mortality.

Pulmonary administration of a doxorubicin-conjugated dendrimer enhances drug exposure to lung metastases and improves cancer therapy

Direct administration of chemotherapeutic drugs to the lungs significantly enhances drug exposure to lung resident cancers and may improve chemotherapy when compared to intravenous administration. Direct inhalation of uncomplexed or unencapsulated cytotoxic drugs, however, leads to bolus release and unacceptable lung toxicity. Here, we explored the utility of a 56kDa PEGylated polylysine dendrimer, conjugated to doxorubicin, to promote the controlled and prolonged exposure of lung-resident cancers to cytotoxic drug. After intratracheal instillation to rats, approximately 60% of the dendrimer was rapidly removed from the lungs (within 24h) via mucociliary clearance and absorption into the blood. This was followed by a slower clearance phase that reflected both absorption from the lungs (bioavailability 10–13%) and biodegradation of the dendrimer scaffold. After 7days, approximately 15% of the dose remained in the lungs. A syngeneic rat model of lung metastasised breast cancer was subsequently employed to compare the anticancer activity of the dendrimer with a doxorubicin solution formulation after intravenous and pulmonary administration. Twice weekly intratracheal instillation of the dendrimer led to a >95% reduction in lung tumour burden after 2weeks in comparison to IV administration of doxorubicin solution which reduced lung tumour burden by only 30–50%. Intratracheal instillation of an equivalent dose of doxorubicin solution led to extensive lung-related toxicity and death withinseveral days of a single dose. The data suggest that PEGylated dendrimers have potential as inhalable drug delivery systems to promote the prolonged exposure of lung-resident cancers to chemotherapeutic drugs and to improve anti-cancer activity.

Clinical utility of hepatitis B surface antigen levels during the natural history and treatment of chronic hepatitis B infection.

IntroductionHepatitis B surface antigen (HBsAg) level quantitation may be helpful for understanding the natural history of the disease and its response to treatment.AimTo determine the serum HBsAg levels during the different phases of chronic hepatitis B (CHB) infection and HBsAg levels of patients who are on treatment with oral antiviral drugs.Material and methodsPatients were categorized in four groups: 9 patients in the immune clearance (IC) phase, 46 patients in the inactive carrier (INC) phase, 25 patients in the reactivated HBeAg negative disease (END) phase and 60 HBeAg negative patients who were on treatment with oral antiviral drugs. HBsAg levels were compared between all groups. HBsAg and HBV DNA levels were compared in three phases of HBV infection. Patients on treatment were divided into two groups, taking lamivudine (L) and taking tenofovir (T). HBsAg levels were compared between END, L and T groups.ResultsThe HBsAg levels were different between each phase of CHB (p < 0.0001). HBsAg levels were highest in the IC phase and lowest in the INC phase. The HBsAg/HBV DNA ratio was significantly higher in the INC phase than the END and IC phases (p < 0.0001). HBsAg levels were higher in the END phase than the INC phase (p < 0.0001) and higher than the treatment group (p = 0.007). The HBsAg levels had a good correlation with HBV DNA in the natural course of CHB (r = 0.72, p < 0.0001). HBsAg levels were higher in the END group than the L and T groups (p < 0.05). HBsAg levels were higher in the L than the T group (p < 0.05).ConclusionsThis study demonstrates that HBsAg levels vary during the natural history of chronic hepatitis B infection. Also, the monitoring of HBsAg levels may help us to determine the best management strategy and to decide future treatment algorithms.

HBsAg levels in HBeAg-positive chronic hepatitis B patients with different immune conditions.

To investigate hepatitis B surface antigen (HBsAg) levels in patients with HBeAg-positive chronic hepatitis B (CHB) and different immune conditions. HBeAg-positive CHB patients with different immune conditions were enrolled in this cross-sectional study. These patients were grouped according to the following criteria: immune-tolerant patients, IT group; patients with a mild immune response in the immune clearance phase, IC-Mild group; and patients with a dramatic immune response in the immune clearance phase and exhibiting acute on chronic liver failure (ACLF), ACLF group. All these patients had not previously received antiviral therapy and were enrolled at a pre-settled ratio of 2:2:1. Serum HBsAg levels and the correlation between serum HBsAg level and serum hepatitis B virus (HBV) DNA level were evaluated in these groups. In total, 180 HBeAg-positive CHB patients [IT group (n = 72), IC-Mild group (n = 72), and ACLF group (n = 36)] were enrolled in this study. The median serum HBsAg levels varied among the groups (P < 0.001): IT, 4.86 log10 IU/mL; IC-Mild, 3.97 log10 IU/mL; and ACLF, 3.57 log10 IU/mL. Serum HBsAg level showed a moderate positive correlation with serum HBV-DNA level in the IC-Mild group (r = 0.60, P < 0.001), but exhibited a weaker correlation in the IT (r = 0.52, P < 0.001) and ACLF groups (r = 0.51, P = 0.001). The ratio of HBsAg/HBV DNA did not differ significantly among the IT, IC-Mild, and ACLF groups (medians: 0.56, 0.55, and 0.56, respectively; P = 0.179). Serum HBsAg levels varied significantly in HBeAg-positive patients with different immune conditions. These findings may have important implications for understanding the immune clearance of HBV in HBeAg-positive CHB patients.

HBeAg negative variants and their role in the natural history of chronic hepatitis B virus infection.

Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become "inactive HBsAg carriers". However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.

クラウチングスタートのブロッククリアランスにおける力発揮と動作の関係

Block clearance at the start of a sprint is a crucial phase of the race. However, the relationship between the force applied during the block clearance phase and the block clearance movement from the set position has not been entirely clarified. In this study, we examined this relationship by focusing on the behavior of the center of gravity of the whole body during the block clearance phase in a crouching start. Eight sprinters performed a starting dash from a starting block, as would occur in a sprint race. During the block clearance phase, the forces applied to the front and rear starting blocks were measured, and the block clearance movements were analyzed. The force applied during the block clearance phase was evaluated for whether it was close to the horizontal direction on the basis of the BLC (BLC=horizontal component of the impulse applied to the starting blocks/impulse applied to the starting blocks). There was a significant relationship (p<0.05) between the BLC and the angular displacement of the angle of the trunk during the block clearance phase. Also, the BLC was related to the rotational movement in the block clearance phase. In the entire block clearance phase for a high-BLC subject, the extensional movement occurred after the rotational movement. These sequences in movement of the whole body resulted in the center of gravity of the whole body being close to the horizontal direction. Furthermore, there was a significant relationship (p<0.05) between the BLC and the trunk angle at foot strike on the first step. Thus, during the block clearance phase in a crouching start, it is important for sprinters to accelerate their whole body close to the horizontal, applying their force to the starting block. This acceleration may result in horizontal movement of the body with lowering of the torso.

Dynamic Changes in Mucus Thickness and Ion Secretion during Citrobacter rodentium Infection and Clearance

Citrobacter rodentium is an attaching and effacing pathogen used as a murine model for enteropathogenic Escherichia coli. The mucus layers are a complex matrix of molecules, and mucus swelling, hydration and permeability are affected by many factors, including ion composition. Here, we used the C. rodentium model to investigate mucus dynamics during infection. By measuring the mucus layer thickness in tissue explants during infection, we demonstrated that the thickness changes dynamically during the course of infection and that its thickest stage coincides with the start of a decrease of bacterial density at day 14 after infection. Although quantitative PCR analysis demonstrated that mucin mRNA increases during early infection, the increased mucus layer thickness late in infection was not explained by increased mRNA levels. Proteomic analysis of mucus did not demonstrate the appearance of additional mucins, but revealed an increased number of proteins involved in defense responses. Ussing chamber-based electrical measurements demonstrated that ion secretion was dynamically altered during the infection phases. Furthermore, the bicarbonate ion channel Bestrophin-2 mRNA nominally increased, whereas the Cftr mRNA decreased during the late infection clearance phase. Microscopy of Muc2 immunostained tissues suggested that the inner striated mucus layer present in the healthy colon was scarce during the time point of most severe infection (10 days post infection), but then expanded, albeit with a less structured appearance, during the expulsion phase. Together with previously published literature, the data implies a model for clearance where a change in secretion allows reformation of the mucus layer, displacing the pathogen to the outer mucus layer, where it is then outcompeted by the returning commensal flora. In conclusion, mucus and ion secretion are dynamically altered during the C. rodentium infection cycle.

HBsAg quantification: useful for monitoring natural history and treatment outcome

The template of hepatitis B virus transcription, the covalently closed circular DNA (cccDNA), plays a key role in the life cycle of the virus and permits the persistence of infection. It has been suggested that hepatitis B surface antigen (HBsAg) quantification reflects the concentration of cccDNA in the liver. In hepatitis B e antigen (HBeAg) positive chronic hepatitis B, HBsAg levels are higherduring the immune tolerance phase than during the immune clearance phase. During the natural history of chronic hepatitis B, serum HBsAg declines progressively from the immune-tolerant to the low replicative phase. In HBeAg negative patients, the combination of low hepatitis B virus (HBV) DNA (<2000IU/ml) and low HBsAg levels (<1000IU/ml) can predict inactive carrier status, low risk of hepatocellular carcinoma, and the probability of HBsAg loss. HBsAg in combination with HBV DNA predicts the outcome of Peg-Interferon therapy: An absence of decline at week 12 is a good predictor of non-response and to stop therapy. Any decline at week 24, suggests that therapy should be continued to 48weeks. Although the decrease in HBsAg decline slow with nucleos(t)ide analogue therapy, a rapid decline can predict future HBsAg seroclearance. A level <100IU/ml during six consecutive months could be a marker of a sustained response after treatment cessation.

HBeAg‐positive chronic hepatitis B: Why do I treat my patients with Nucleos(t)ide Analogs?

The ultimate goal of therapy for hepatitis B virus (HBV) infection is to obtain a clinical benefit for the patient by reducing infection-related complications, including hepatocellular carcinoma (HCC). Two main types of antiviral agents have been approved to treat patients in the immune clearance phase: interferon (IFN) and nucleos(t)ide analogues (NAs). NAs are used in most HBeAg-positive chronic hepatitis B patients for several reasons. They are oral drugs that are taken once a day and can be prescribed to all chronic hepatitis B patients, even those with contraindications for IFN. The current first-line NA options, entecavir (ETV) and tenofovir (TDF), have minimal or no risk of long-term resistance, and the sustained virological response is achieved in almost 100% of adherent HBeAg-positive patients. Tolerance is excellent and the safety profile is good, whereas IFN can be associated with adverse events that affect the patients' quality of life. There is considerable evidence to show that NAs modify the natural history of chronic hepatitis B, and increasing evidence that they reduce the risk of developing HCC. The need for long-term, perhaps indefinite treatment in patients who do not achieve anti-HBe seroconversion is the main limitation of NAs, but this is offset by their excellent tolerance and safety profile.

Histologic Changes in Liver Tissue From Patients With Chronic Hepatitis B and Minimal Increases in Levels of Alanine Aminotransferase: A Meta-analysis and Systematic Review

The level of alanine aminotransferase (ALT) is a marker of hepatitis B severity and response to treatment. However, measurements of ALT level may be of limited use during the immune clearance phase of chronic hepatitis B (CHB) and can be affected by age, weight, and concomitant liver disease. We performed a literature review to determine the proportion of CHB patients with ALT levels of 1- to 2-fold the upper limit of normal who also had significant underlying liver fibrosis (stage ≥2). We performed a Medline search of original articles published before June 2012, and their references; we also searched abstracts from the 2010 and 2011 annual meetings of the American Association for the Study of Liver Diseases and the 2011 and 2012 Digestive Disease Weeks. Studies were included that had 20 or more consecutive treatment-naive CHB patients with 6 months or more of follow-up evaluation, histologic data, and levels of ALT 1- to 2-fold the upper limit of normal. Study heterogeneity was assessed by a Forest plot and Q and I(2) analyses. Sensitivity was measured using 1-study removed analysis. Our analysis included 8 articles and 1 abstract, comprising 683 patients. Based on random-effects modeling, 48% of patients had stage 2 or higher fibrosis (95% confidence interval, 36%-61%). In a sensitivity analysis, exclusion of the study that caused the greatest deflection of the pooled estimate produced a revised estimate of 43%. A subgroup of hepatitis B e antigen-positive and hepatitis B e antigen-negative patients (n = 168 and 170, respectively) showed similar rates of fibrosis (41% vs 47%; P = nonsignificant). Despite heterogeneity in the literature, a substantial proportion of patients with slight increases in ALT level have significant fibrosis. Given the possibility of advanced liver disease, the threshold for antiviral treatment must be individualized. Further studies are needed to investigate patients with modest increases in ALT level.

The fate of inhaled 14C-labeled PCB11 and its metabolites in vivo

BackgroundThe production ban of polychlorinated biphenyl (PCB) technical mixtures has left the erroneous impression that PCBs exist only as legacy pollutants. Some lower-chlorinated PCBs are still being produced and contaminate both indoor and ambient air. ObjectivesTo inform PCB risk assessment, we characterized lung uptake, distribution, metabolism and excretion of PCB11 as a signature compound for these airborne non-legacy PCBs. MethodsAfter delivering [14C]PCB11 to the lungs of male rats, radioactivity in 34 major tissues and 5 digestive matter compartments was measured at 12, 25, 50, 100, 200 and 720min postexposure, during which time the excreta and exhaled air were also collected. [14C]PCB11 and metabolites in lung, liver, blood, digestive matter, urine, feces, and adipose tissues were extracted separately to establish the metabolic profile of the disposition. Results[14C]PCB11 was distributed rapidly to all tissues after 99.8% pulmonary uptake and quickly underwent extensive metabolism. The major tissue deposition of [14C]PCB11 and metabolites translocated from liver, blood and muscle to skin and adipose tissue 200min postexposure, while over 50% of administered dose was discharged via urine and feces within 12h. Elimination of the [14C]PCB11 and metabolites consisted of an initial fast phase (t½=9–33min) and a slower clearance phase to low concentrations. Phase II metabolites dominated in liver blood and excreta after 25min postexposure. ConclusionsThis study shows that PCB11 is completely absorbed after inhalation exposure and is rapidly eliminated from most tissues. Phase II metabolites dominated with a slower elimination rate than the PCB11 or phase I metabolites and thus can best serve as urine biomarkers of exposure.

Storage-Induced Clearance Of RBCs Following Transfusion Occurs Independent Of RBC Age

BackgroundDuring red blood cell (RBC) storage, changes occur that increase the clearance of RBCs following transfusion. RBCs also display unique age related changes that target them for removal in vivo, a process commonly termed RBC senescence. However, whether storage related changes simply reflect acceleration of the normal senescent programs that occur in vivo, or whether all RBCs display equal sensitivity to storage induced alterations that enhance clearance following transfusion remains unknown. As a result, we sought to determine whether enhanced RBC removal following storage simply reflects preferential clearance of older RBCs. MethodsB6 mice expressing green fluorescent protein (GFP) under a H-2Kb promoter were injected with N-hydroxysulfosuccinimide biotin followed by evaluation of biotinylated RBCs at weekly time points post transfusion by staining RBCs with strepavidin and flow cytometric analysis. At approximately 1 or 35 days post-biotinylation, blood was harvested into citrate phosphate dextrose adenine (CPDA) and RBCs were immediately transfused or stored in CPDA for 21 days prior to transfusion. Prior to transfusion, the percent of RBCs that remained biotinylated was enumerated. Following transfusion, mice were bleed at 10 minutes, 1 hour or 2 hours followed by daily bleeds for 7 days and weekly thereafter and the ratio of biotin and GFP double positive to GFP single positive RBCs was examined by staining RBCs with strepavidin followed by flow cytometric analysis. ResultsImmediately after whole mouse biotinylation, nearly 100% of donor RBCs became strepavidin positive. The percent strepavidin positivity gradually decreased until approximately 20% of the total RBCs remained strepavidin positive 35 days post-biotinylation. RBCs harvested 35 days post biotinylation into CPDA and transfused immediately exhibited gradual clearance over time, such that very few transfused RBCs were detectable 40 days post transfusion. In contrast, the percent of transfused RBCs that remained biotin positive rapidly declined to undetectable levels within 7 days following transfusion. Transfused RBCs harvested only 1 day following biotinylation failed to display enhanced clearance during the same 7 day interval. In contrast, the percent of biotin positive RBCs remained unchanged during storage. In addition, transfusion of stored RBCs failed to result in selective clearance of biotin positive RBCs during the initial clearance phase, although biotin positive RBCs appeared to retain enhanced rates of removal following the initial phase of RBC removal. ConclusionOlder RBCs appear to retain signals that result in preferential removal compared to younger RBCs following harvesting, processing and transfusion into a new recipient. Preferential clearance of older RBCs does not appear to reflect a biotinylation artifact, as newly biotinylated RBCs failed to display similar increases in RBC clearance. However, storage induced changes do not appear to result in selective removal of older RBCs, as biotinylated and non-biotinylated RBCs displayed significant removal during the initial phase of clearance following transfusion. Taken together, these results suggest that older RBCs retain senescent markers that results in enhanced clearance, but that RBC storage induces unique RBC changes that marks them for rapid clearance largely independent of RBC age. Disclosures:Zimring:Immucor Inc.: Research Funding; Terumo: Research Funding; Haemonetics: Consultancy; Cerus: Honoraria.

Hepatitis B virus depicts a high degree of conservation during the immune-tolerant phase in familiarly transmitted chronic hepatitis B infection: deep-sequencing and phylogenetic analysis.

When intrafamilial transmission of hepatitis B virus (HBV) occurs, a virus with the same characteristics interacts with diverse hosts' immune systems and may thus result in different mutations to escape immune pressure. In this study, the HBV genomic characterization was assessed longitudinally after intrafamilial transmission using nucleotide sequence data of phylogenetic and mutational analyses, including those obtained by deep-sequencing for the first time. Furthermore, HBeAg-anti-HBe profile and variability of HBV core-derived epitopes were also evaluated. Strong evidence was obtained from intrafamilial transmission of HBV genotype D1 by phylogenetic inferences. HBV isolates exhibited high degree (~99%) of genomic conservation for almost 20 years, when patients were persistently HBeAg positive with normal amino transferase levels. This identity remained high among immune-tolerant siblings. In contrast, it diminished significantly (P = 0.02) when the mother cleared HBeAg (immune clearance phase). By deep-sequencing, the quantitative analysis of the dynamics of basal core promoter (BCP) (A1762T, G1764A; A1766C; T1773C; 8-bp deletion; and other) and precore (G1896A) variants among HBV isolates from family members exhibited differences during the follow-up. However, only those from the mother showed amino acid variations at core protein that would impair their MHC-II binding. Hence, when intrafamilial transmission occurs, HBV was highly conserved under the immune-tolerant phase, but it exhibited mutations more frequently during the immune clearance phase. The analysis of the HBV BCP and precore mutants after intrafamilial HBV transmission contributes to a better understanding of how they evolve over time.

Mouse in Vivo Neutralization of Escherichia coli Shiga Toxin 2 with Monoclonal Antibodies

Shiga toxin-producing Escherichia coli (STEC) food contaminations pose serious health concerns, and have been the subject of massive food recalls. STEC has been identified as the major cause of the life-threatening complication of hemolytic uremic syndrome (HUS). Besides supportive care, there currently are no therapeutics available. The use of antibiotics for combating pathogenic E. coli is not recommended because they have been shown to stimulate toxin production. Clearing Stx2 from the circulation could potentially lessen disease severity. In this study, we tested the in vivo neutralization of Stx2 in mice using monoclonal antibodies (mAbs). We measured the biologic half-life of Stx2 in mice and determined the distribution phase or t1/2 α to be 3 min and the clearance phase or t1/2 β to be 40 min. Neutralizing mAbs were capable of clearing Stx2 completely from intoxicated mouse blood within minutes. We also examined the persistence of these mAbs over time and showed that complete protection could be passively conferred to mice 4 weeks before exposure to Stx2. The advent of better diagnositic methods and the availability of a greater arsenal of therapeutic mAbs against Stx2 would greatly enhance treatment outcomes of life threatening E. coli infections.

Anti‐HBs seroconversion during treatment with entecavir in a patient with chronic hepatitis B virus infection on hemodialysis

Hepatitis B (HBV) virus infection is one of the most important causes of liver disease in patients with end-stage renal failure on hemodialysis. The natural history of chronic HBV infection acquired in childhood starts with an immune tolerant phase, followed by an immune clearance phase that may lead to the inactive carrier state or the development of chronic liver disease. Information on antiviral therapy administered very early during the immune clearance phase are lacking and no data exist on the treatment of early immune activation in the hemodialysis setting. This report describes the case of a patient affected by end-stage renal failure and HBeAg-positive chronic HBV virus infection treated very early during the immune clearance phase of HBV infection with an adjusted-dose of nucleoside analogue entecavir. The patient achieved a very rapid HBV-DNA undetectability, anti-HBe, and anti-HBs seroconversion. This is the first report of antiviral therapy with entecavir started during the immune reactive phase of HBV infection in a patient on hemodialysis and it suggests that antiviral treatment can enhance the effects of host immune activation resulting in biochemical, serological, and viral response, even in end-stage renal failure patients with partial immunodeficiency. Antiviral therapy with entecavir in the setting of hemodialysis was safe and well tolerated.

Clinical implications of the titer of serum hepatitis B surface antigen during the natural history of hepatitis B virus infection

Although there are some differences in hepatitis B surface antigen (HBsAg) titers in infection with different hepatitis B virus (HBV) genotypes, the HBsAg titers for each HBV genotype have not been evaluated extensively. The aim of this study was to investigate HBsAg titers during the natural history of patients infected with HBV in Korea, where the HBV genotype C is endemic exclusively. Four hundred fifteen patients were enrolled retrospectively and classified according to definitions of the natural phases of HBV infection. In total, 73, 118, 147, and 77 patients were classified in the immune tolerance, immune clearance, low replicative, and HBeAg-negative hepatitis phases, respectively. HBsAg titers (4.35 ± 0.67, 3.74 ± 0.68, 2.39 ± 1.23, and 3.29 ± 0.64 log(10) IU/ml) were significantly different in the immune tolerance, immune clearance, low replicative, and HBeAg-negative hepatitis phases, respectively (P < 0.001). The ratio of HBsAg to HBV DNA was highest in the low replicative phase (1.13 ± 0.71, all P < 0.001) and second highest in the HBeAg-negative hepatitis phase (0.58 ± 0.18, all P < 0.05). In multivariate analysis of all patients, the HBsAg titers did not correlate with alanine aminotransferase. However, the HBsAg titers correlated with age (P = 0.038), platelet count (P < 0.001) and HBV DNA (P < 0.001). In subgroup analysis, the HBsAg titers correlated with HBV DNA in all phases (P < 0.001), except for the HBeAg-negative hepatitis phase. HBsAg titers were significantly different across the four phases of the natural history of the infection and correlated significantly with HBV DNA titer in genotype C chronic hepatitis B patients. The HBsAg titer could be used as a biomarker to differentiate the natural history of HBV infection.

Serum HBsAg quantification in treatment-naïve Indian patients with chronic hepatitis B

There is paucity of Indian data regarding serum HBsAg levels (qHBsAg) in treatment-naïve chronic hepatitis B (CHB). This study was done to determine correlation of qHBsAg with hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels and its ability to independently categorize subgroups of CHB. We studied 131 treatment-naive CHB patients and initially classified them based on HBeAg status. The HBeAg-positive group was further classified into immune tolerance (IT) and immune clearance (IC) phases based on serum alanine aminotransferase. HBeAg-negative patients were classified into low replicators (LR) and HBeAg-negative chronic hepatitis (ENH) based on DNA levels. HBsAg quantification was performed using the Architect chemiluminescence system. HBeAg-positive patients had higher DNA (7.89 vs. 2.69 log10 IU/mL) and higher qHBsAg (4.60 vs. 3.85 log10 IU/mL) compared to the HBeAg-negative group. Good correlation between qHBsAg and DNA was seen in HBeAg-positive (ρ = 0.6, p < 0.001) but not in HBeAg-negative CHB (ρ = 0.2). A qHBsAg level greater than 4.39 log10 IU/mL predicted HBeAg-positive state with 81 % sensitivity and 85 % specificity. However, among HBeAg-negative CHB, qHBsAg failed to discriminate between LR and ENH. A single point estimation of qHBsAg in treatment-naïve patients could predict replicative HBeAg-positive CHB, but was not helpful in defining replicative status in the HBeAg-negative CHB.

Evaluation of neurobehavioral and neuroinflammatory end-points in the post-exposure period in rats sub-acutely exposed to manganese

Manganese (Mn) can cause manganism, a neurological disorder similar to Parkinson’ Disease (PD). The neurobehavioral and neuroinflammatory end-points in the Mn post exposure period have not been studied yet. Rats were injected on alternate days with 8 doses of MnCl2 (25mg/kg) or saline, then euthanized 1, 10, 30 or 70 days following the last dose. Whole-blood (WB) (p<0.05), urine (p<0.05) and brain cortical (p<0.0001) Mn levels were significantly increased 24h after the last dose. Decreases in the rats’ ambulation were noted 1, 10 and 30 days after the last Mn dose (p<0.001; p<0.05; p<0.001, respectively) and also in the rearing activity at the four time-points (p<0.05). Cortical glial fibrillary acid protein immunoreactivity (GFAP-ir) was significantly increased at 1, 10, 30 (p<0.0001) and 70 (p<0.001) days after the last Mn dose, as well as tumor necrosis α (TNF-α) levels (p<0.05) but just on day 1. Taken together, the results show that, during the 70-day clearance phase of Mn, the recovery is not immediate as behavioral alterations and neuroinflammation persist long after Mn is cleared from the cortical brain compartment.