Chemical upcycling of PVC-containing plastic wastes by thermal degradation and catalysis in a chlorine-rich environment

Chlorine (Cl)-containing chemicals, including hydrogen chloride, generated during thermal degradation of polyvinyl chloride (PVC) and corresponding mixture impede the chemical recycling of PVC-containing plastic wastes. While upgrading plastic-derived vapors, the presence of Cl-containing chemicals may deactivate the catalysts. Accordingly, herein, catalytic upgrading of pyrolysis vapor prepared from a mixture of PVC and polyolefins is performed using a fixed-bed reactor comprising zeolites. Among the H-forms of zeolites (namely, ZSM-5, Y, β, and chabazite) used in this study, a higher yield of gas products composed of hydrocarbons with lower carbon numbers is obtained using H-ZSM-5, thus indicating further decomposition of the pyrolysis vapor to C1-C4 hydrocarbons on it. Although the formation of aromatic compounds is better on H-ZSM-5, product distributions can be adjusted by further modifying the acidic properties via the alteration of the Si/Al molar ratio, and maximum yields of C1-C4 compounds (60.8%) and olefins (64.7%) are achieved using a Si/Al molar ratio of 50. Additionally, metal ion exchange on H-ZSM-5 is conducted, and upgrading of PVC-containing waste-derived vapor to aromatic chemicals and small hydrocarbon molecules was successfully performed using Co-substituted H-ZSM-5. It reveals that the highest yield of gas products on 1.74 wt% cobalt (Co)-substituted H-ZSM-5 is acquired via the selection of an appropriate metal and metal ion concentration adjustment. Nevertheless, introduction of excess Co into the H-ZSM-5 surface decreases the cracking activity, thereby implying that highly distributed Co is required to achieve excellent cracking activity. The addition of Co also adjusted the acid types of H-ZSM-5, and more Lewis acid sites compared to Brønsted acid sites selectively produced olefins and naphthenes over paraffins and aromatics. The proposed approach can be a feasible process to produce valuable petroleum-replacing chemicals from Cl-containing mixed plastic wastes, contributing to the closed loops for upcycling plastic wastes.

Stabilization of acid-rich bio-oil by catalytic mild hydrotreating

Although liquid products derived from the pyrolysis of biomass are promising for the production of petroleum-like hydrocarbon fuels, the catalytic burden of hydrodeoxygenation must be reduced to achieve feasible upgrading processes. Herein, mild hydrotreating of an acid-rich biomass pyrolysis oil (bio-oil) with an unusually high total acid number (588 mg KOH/g bio-oil) was performed to stabilize the low-quality bio-oil. Ru-added TiO₂-supported transition metal catalysts stabilized the bio-oil by reducing its acidity more compared to what could be achieved by Ru-free catalysts; this process also leads to lower loss of organic compounds compared to when using a Ru/TiO₂ catalyst. Based on the performance of transition metal catalysts, including Ni, Co, and Cu, supported on TiO₂, tungstate-zirconia, or SiO₂, supported bimetallic catalysts were prepared by adding Ru to the TiO₂-supported metal catalysts. The bimetallic catalysts Ru/Ni/TiO₂ and Ru/Co/TiO₂ exhibited good decarboxylation activity for the removal of carboxylic acids and a higher yield of organic compounds compared to that provided by Ru, which can be deemed appropriate for feedstocks when hydrodeoxygenation needs to suppress the loss of organic reactants. Using these catalysts, the carboxylic acid concentration was reduced to 319-323 mg KOH/g bio-oil with organic yields of 62-63 wt% at reaction temperatures 150-170 °C lower than the temperature required for direct conversion of carboxylic acids to alcohols or deoxygenates. The improved catalytic hydrotreating activity of Ru-added transition metals can be attributed to the high acid site densities of these catalysts along with their improved hydrogenation activities.

Improved catalytic depolymerization of lignin waste using carbohydrate derivatives

CARBOHYDRATE-: or sugar-derived compounds were used as environmentally friendly additives for the depolymerization of Kraft lignin waste and organosolv lignin prepared from Miscanthus giganteus. The yields of the aromatic monomers obtained from Kraft lignin increased from 5.1 to 49.2% with the addition of mannitol, while those obtained from organosolv lignin increased from 44.4 to 83.0% with the addition of sucrose. This improved lignin depolymerization was also confirmed by gel permeation chromatography and nuclear magnetic resonance spectroscopy. The above results clearly indicate the beneficial effects of carbohydrate derivatives on the lignin depolymersization process, more specifically, suggesting that the presence of carbohydrates improve the lignin depolymerization of lignocellulose, as observed for the raw lignocellulose feed.

SiO2@MnO x @Na2WO4@SiO2 core-shell-derived catalyst for oxidative coupling of methane

SiO₂@MnO_x@Na₂WO₄@SiO₂ core–shell catalysts were prepared and their fabrication was confirmed using transmission electron microscopy. The formation of Mn-based nanosheets on the silica spheres is important for the deposition of nanoscopic Na₂WO₄. The SiO₂@MnO_x@Na₂WO₄@SiO₂ core–shell catalysts were used for the oxidative coupling of methane at a temperature of 700–800 °C at which the nanostructures were completely destroyed. Although the core–shell structures did not survive the high-temperature oxidative coupling of methane, the selective production of olefins and paraffins can be attributed to highly dispersed Na₂WO₄ derived from confined core–shell structures.

SiO₂@MnO_x@Na₂WO₄@SiO₂ core–shell catalysts were prepared for the oxidative coupling of methane.

Study on the unsteady state oxidative coupling of methane: effects of oxygen species from O2, surface lattice oxygen, and CO2 on the C2+ selectivity

This study examined the effects of oxygen species on the unsteady-state oxidative coupling of methane (OCM) using a lengthy catalyst bed of Na₂WO₄/Mn/SiO₂. The reaction conditions, including the methane-to-oxygen ratio, ratio of feed gas dilution by N₂, quantity of catalyst, and feed flow rate were adjusted for the continuous flow fixed bed reaction system. While the O₂ gas initiated methyl radical formation from methane, the surface lattice oxygen atoms improved the dehydrogenation of paraffins to olefins without significant activation of methane. The addition of CO₂ as a mild oxidizing agent was also tested and slightly improved OCM selectivity with slightly lower methane conversion were observed.

This study examined the effects of oxygen species on the unsteady-state oxidative coupling of methane (OCM) using a lengthy catalyst bed of Na₂WO₄/Mn/SiO₂.

Chronic hepatitis B infection and non-hepatocellular cancers: A hospital registry-based, case-control study

Background

Prior epidemiological evidences suggest that hepatitis B virus (HBV) infection is linked to cancers other than hepatocellular carcinoma. This prospective hospital registry-based case-control study aimed to investigate the sero-epidemiological association between chronic HBV infection and various types of cancer.

Methods

95,034 patients with first-diagnosed non-hepatocellular malignancy in a tertiary hospital between 2007 and 2014; and 118,891 non-cancer individuals as controls from a health promotion center were included. Cases and controls were compared for HBV surface antigen (HBsAg) positivity by conditional regression with adjustment for age, hypertension, diabetes, body mass index, alcohol consumption, smoking status and cholesterol level in both genders.

Results

An analysis of matched data indicated significant associations of HBV infection with lymphoma (adjusted odds ratio[AOR] 1.53 [95% CI 1.12–2.09] in men and 3.04 [1.92–4.82] in women) and biliary cancer (2.59[1.98–3.39] in men and 1.71[1.16–2.51] in women). Cervical (1.49[1.11–2.00]), uterine (1.69[1.09–2.61]), breast (1.16[1.02–1.32]), thyroid (1.49[1.28–1.74]), and lung cancers (1.79[1.32–2.44]) in women; and skin cancer (5.33[1.55–18.30]) in men were also significantly related to HBV infection.

Conclusions

Chronic HBV infection is associated with several malignant disorders including lymphoma, and biliary, cervical, uterine, breast, thyroid, lung, and skin cancers. Our findings may offer additional insights into the development of these neoplasms and may suggest the need to consider HBV screening in cancer patients and cancer surveillance in HBV-infected subjects.

Efficacy and safety of entecavir versus lamivudine over 5 years of treatment: A randomized controlled trial in Korean patients with hepatitis B e antigen-negative chronic hepatitis B

BACKGROUND/AIMS

Long-term data on antiviral therapy in Korean patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) are limited. This study evaluated the efficacy and safety of entecavir (ETV) and lamivudine (LAM) over 240 weeks.

METHODS

Treatment-naive patients with HBeAg-negative CHB were randomized to receive ETV 0.5 mg/day or LAM 100 mg/day during the 96 week double-blind phase, followed by open-label treatment through week 240. The primary endpoint was the proportion of patients with virologic response (VR; hepatitis B virus [HBV] DNA<300 copies/mL) at week 24. Secondary objectives included alanine aminotransferase (ALT) normalization and emergence of ETV resistance (week 96), VR and log reduction in HBV DNA levels (week 240), and safety evaluation.

RESULTS

In total, 120 patients (>16 years old) were included (ETV, n=56; LAM, n=64). Baseline characteristics were comparable between the two groups. A significantly higher proportion of ETV-treated patients achieved VR compared to LAM at week 24 (92.9% vs. 67.2%, P=0.0006), week 96 (94.6% vs. 48.4%, P<0.0001), and week 240 (95.0% vs. 47.6%, P<0.0001). At week 96, ALT normalization was observed in 87.5% and 51.6% of ETV and LAM patients, respectively (P<0.0001). Virologic breakthrough occurred in one patient (1.8%) receiving ETV and 26 patients (42.6%) receiving LAM (P<0.0001) up to week 96. Emergence of resistance to ETV was not detected. The incidence of serious adverse events was low and unrelated to the study medications.

CONCLUSIONS

Long-term ETV treatment was superior to LAM, with a significantly higher proportion of patients achieving VR. Both treatments were well tolerated.

Effective depolymerization of concentrated acid hydrolysis lignin using a carbon-supported ruthenium catalyst in ethanol/formic acid media

Lignin isolated by two-step concentrated acid hydrolysis of empty fruit bunch (EFB) was effectively depolymerized into a high-quality bio-oil using formic acid (FA) as an in-situ hydrogen source and Ru/C as a catalyst in supercritical ethanol. A bio-oil yield of 66.3wt% with an average molecular weight of 822g/mol and an aromatic monomer content of 6.1wt% was achieved at 350°C and a FA-to-lignin mass ratio of 3 after a reaction time of 60min. The combination of Ru/C and FA also resulted in a significant reduction in the oxygen content of the bio-oil by ∼60% and a corresponding increase in the higher heating value (HHV) to 32.7MJ/kg due to the enhanced hydrodeoxygenation activity. An examination of the FA decomposition characteristics revealed that Ru/C provides a greater increase in the rate of hydrogen production from FA, explaining the efficient depolymerization of lignin in a combined system.

Sclerosing encapsulating peritonitis in a long-term propranolol user

Sclerosing encapsulating peritonitis (SEP) is a rare cause of bowel obstruction that is characterized by the encasement of the small bowel by a thick, whitish, and fibrous membrane. The pathophysiology of SEP is poorly understood and preoperative diagnosis is difficult. Previous reports suggest that SEP may be linked to the chronic use of β-adrenergic blockers. A 46-year-old man with liver cirrhosis and end-stage renal disease on hemodialysis presented with recurrent abdominal pain and borborygmi. He had been taking propranolol to prevent bleeding from gastroesophageal varices for the past 15 years. Abdominal computed tomography showed ileal loops encapsulated by soft tissue with dilatation of the proximal small bowel on the right side of the abdomen. Barium follow-through showed conglomerated distal ileal loops with a cauliflower-like appearance. Explorative laparotomy revealed a thick, fibrous, whitish capsule encapsulating the ileal loops. The covering membrane was dissected and excised, resulting in an improvement in symptoms after surgery. Accordingly, a final diagnosis of SEP was made. Due to the lack of other apparent causes for SEP, we conclude that in this case, the long-term use of propranolol may be associated with the development of SEP.

Highly Dispersed Pt Nanoparticles for the Production of Aromatic Hydrocarbons by the Catalytic Degrading of Alkali Lignin

Aromatic hydrocarbons were produced from lignin, a complex natural amorphous polymer commonly regarded as by-product of the pulping process and from biofuel production. The catalytic decomposition of lignin using supported Pt catalysts was performed to produce small molecule hydrocarbons. Aromatic small-molecule hydrocarbon products were identified and quantified using GC/MS and GC-FID, which demonstrated that 27.6% of aromatic hydrocarbons were obtained from the activated carbon-supported Pt (Pt/AC) catalyst which had the highest Pt surface area.

Catalytic Depolymerization of Alkali Lignin Using Supported Pt Nanoparticle Catalysts

Alkali lignin, a byproduct of the pulping process, was depolymerized using Pt nanoparticle catalysts. A depolymerized lignin with a lower molecular weight was obtained and characterized with GPC and NMR. 31P-NMR using OH-sensitive probing molecules showed the formation of guaiacyl OHs during the reaction, indicating the cleavage of guaiacyl ether bonds.

Catalytic Reforming of Lignin-Derived Bio-Oil Over a Nanoporous Molecular Sieve Silicoaluminophosphate-11

Catalytic pyrolysis of lignin, a major constituent of biomass, was performed. A nanoporous molecular sieve silicoaluminophosphate-11 (SAPO-11) was selected as catalyst. Thermogravimetric analysis showed that 500 degrees C was the optimal pyrolysis temperature. Pyrolyzer-gas chromatography/mass spectroscopy was used to investigate the pyrolysis product distribution. Production of phenolics, the dominant product from the pyrolysis of lignin, was promoted by the increase in the catalyst dose. In particular, low-molecular-mass phenolics were produced more over SAPO-11, while high-molecular-mass phenolics and double-bond-containing phenolics were produced less. The fraction of aromatic compounds, including benzene, toluene, xylene, and ethylbenzene, was also increased by catalytic reforming. The catalytic effects were more pronounced when the catalyst/biomass ratio was increased. The enhanced production of aromatic compounds by an acidic catalyst obtained in this study is in good agreement with the results of previous studies.

Comprehensive outcomes of on- and off-antiviral prophylaxis in hepatitis B patients undergoing cancer chemotherapy: A competing risks analysis

Although antiviral prophylaxis is essential in hepatitis B patients in the context of cancer chemotherapy, there is little evidence-based consensus regarding the appropriate prevention strategy depending on the underlying type of cancer and viral status. This retrospective study included a comprehensive cohort of 302 hepatitis B surface antigen-positive patients with various cancers undergoing chemotherapy and antiviral prophylaxis. The rates of hepatitis B virus (HBV) reactivation during antiviral therapy (>1 log10 IU/mL increase or positive conversion of serum HBV DNA) and relapse when off antivirals ([re]appearance of HBV DNA >2,000 IU/ml with related alanine aminotransferase elevation) were evaluated, together with the associated risk factors, in a competing risks analysis where cancer death was considered as the competing event. During antiviral prophylaxis, HBV was reactivated in six patients (1.9%), who had leukemia (n = 4) or lymphoma (n = 2) and were treated with lamivudine (n = 4) or entecavir (n = 2). The incidence rate of HBV relapse in 127 off-prophylaxis patients was 21.3% during a median post-antiviral period of 11.7 months. Lymphoma, pre-prophylactic HBV DNA ≥2,000 IU/ml, and age ≥50 years were independent predictors of off-treatment HBV relapse (adjusted hazard ratios 5.25, 3.07, and 0.34, respectively; Ps < 0.05). Antiviral and anticancer drugs, duration of consolidation on antiviral prophylaxis, and HBeAg positivity were not independent predictors. In conclusion, hepatitis B flare-ups are not rare in patients receiving cancer chemotherapy during and after anti-HBV prophylaxis, even when potent antivirals are used. Patients with hematopoietic or lymphoid neoplasms or high viral burdens should receive prolonged and powerful HBV prophylaxis. J. Med. Virol. 88:1576-1586, 2016. © 2016 Wiley Periodicals, Inc.

Hydro- and solvothermolysis of kraft lignin for maximizing production of monomeric aromatic chemicals

The hydro-/solvothermolysis of kraft lignin using water and ethanol as a solvent were investigated in this study. The effect of the water-to-ethanol ratio on the yields of monomeric aromatic chemicals (MACs) and the kinetic behavior of MACs was studied in a series of batch experiments. The yields of MACs other than catechol increased as the ratio of ethanol increased, and the content of the total MACs in bio-crude oil (BCO) reached 35% when the ratio of ethanol was 100% at a reaction temperature of 300 °C. The formation of phenol, guaiacol, and alkylguaiacols was enhanced in ethanol, while the formation of catechol was dominant in water. The formation of more substituted MACs such as vanillin, acetoguaiacone, and homovanillic acid was not affected by the solvent. The role of reaction parameters on the yields of MACs was elucidated, and the main reaction pathways in water and in ethanol were proposed.

HBsAg seroclearance after nucleoside analogue therapy in patients with chronic hepatitis B: clinical outcomes and durability

OBJECTIVE

Little is known about the long-term clinical outcome and durability of HBsAg seroclearance following nucleos(t)ide analogue (NUC) therapy in patients with chronic hepatitis B (CHB).

DESIGN

During a median follow-up period of 6 years (33 567 patient-years) of 5409 CHB patients who were initially treated with lamivudine or entecavir, a total of 110 achieved HBsAg seroclearance (0.33% annual seroclearance rate) and were included in this study.

RESULTS

Baseline alanine aminotransferase (ALT) level >5 times of upper limit of normal was associated with higher probability of HBsAg seroclearance (HR 1.80, p<0.01), while HBeAg positivity (HR 0.46, p<0.01), high HBV DNA level (log(10) IU/mL; HR 0.61, p<0.01), and cirrhosis (HR 0.48, p<0.01) were inversely associated with the probability of HBsAg seroclearance by multivariable analysis. During follow-up for 287 patient-years after HBsAg seroclearance, only two patients with baseline cirrhosis developed hepatocellular carcinoma (HCC) or died (0.7% annual risk), which was of a significantly lower rate compared with propensity score-matched patients without HBsAg seroclearance (HR 0.09, p<0.01). HBsAg reversion and/or HBV DNA reversion occurred in 18 patients, most of which were transient with extremely low serum levels of HBsAg (0.05-1.00 IU/mL) and HBV DNA (17-1818 IU/mL). None required retreatment. The cumulative probability of anti-HBs seroconversion (detection of anti-HBs) at 4 years was 67.4% by Kaplan-Meier analysis. Selection for lamivudine-resistance HBV mutants during treatment was not associated with composite reversion (p=0.66).

CONCLUSIONS

HBsAg seroclearance achieved after NUC treatment was associated with favourable clinical outcomes and was durable in most cases during long-term follow-up.

Comparative study on two-step concentrated acid hydrolysis for the extraction of sugars from lignocellulosic biomass

Among all the feasible thermochemical conversion processes, concentrated acid hydrolysis has been applied to break the crystalline structure of cellulose efficiently and scale up for mass production as lignocellulosic biomass fractionation process. Process conditions are optimized by investigating the effect of decrystallization sulfuric acid concentration (65-80 wt%), hydrolysis temperature (80°C and 100°C), hydrolysis reaction time (during two hours), and biomass species (oak wood, pine wood, and empty fruit bunch (EFB) of palm oil) toward sugar recovery. At the optimum process condition, 78-96% sugars out of theoretically extractable sugars have been fractionated by concentrated sulfuric acid hydrolysis of the three different biomass species with 87-90 g/L sugar concentration in the hydrolyzate and highest recalcitrance of pine (softwood) was determined by the correlation of crystallinity index and sugar yield considering reaction severity.

Mortality, liver transplantation, and hepatocellular carcinoma among patients with chronic hepatitis B treated with entecavir vs lamivudine

BACKGROUND & AIMS

Little is known about whether the antiviral agent entecavir is more effective than a less potent drug, lamivudine, in reducing the risk of death and hepatocellular carcinoma (HCC) in patients with chronic hepatitis B.

METHODS

We performed a retrospective analysis of data from 5374 consecutive adult patients with chronic hepatitis B, treated with entecavir (n = 2000) or lamivudine (n = 3374), at a tertiary referral hospital in Seoul, Korea, from November 1, 1999, through December 31, 2011. Data were collected from patients for up to 6 years and analyzed by a multivariable Cox proportional hazards model for the entire cohort and for propensity score-matched cohorts.

RESULTS

During the study period, 302 patients (5.6%) died, 169 (3.1%) received a liver transplant, and 525 (9.8%) developed HCC. Multivariable analyses showed that compared with lamivudine, entecavir therapy was associated with a significantly lower risk of death or transplantation (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.38-0.64), but a similar risk of HCC (HR, 1.08; 95% CI, 0.87-1.34). In the 1792 overall propensity-matched pairs, entecavir again was associated with a significantly lower risk of death or transplantation (HR, 0.49; 95% CI, 0.37-0.64) and a similar risk of HCC (HR, 1.01; 95% CI, 0.80-1.27). Entecavir also reduced the risk of death or transplantation, compared with lamivudine, in 860 pairs of patients with cirrhosis (HR, 0.42; 95% CI, 0.31-0.57) but there were no differences in risk for HCC (HR, 1.00; 95% CI, 0.78-1.28). However, entecavir and lamivudine did not have significantly different effects on clinical outcome in 878 pairs of patients without cirrhosis.

CONCLUSIONS

In a retrospective study of 5374 patients with chronic hepatitis B virus infection, entecavir therapy was associated with a significantly lower risk of death or transplantation than lamivudine. However, the drugs did not have different effects on HCC risk.

Rescue therapy with adefovir in decompensated liver cirrhosis patients with lamivudine-resistant hepatitis B virus

Background/Aims

Adefovir dipivoxil (ADV) is a nucleotide analogue that is effective against lamivudine-resistant hepatitis B virus (HBV). The aim of this study was to determine the long-term clinical outcomes after ADV rescue therapy in decompensated patients infected with lamivudine-resistant HBV.

Methods

In total, 128 patients with a decompensated state and lamivudine-resistant HBV were treated with ADV at a dosage of 10 mg/day for a median of 33 months in this multicenter cohort study.

Results

Following ADV treatment, 86 (72.3%) of 119 patients experienced a decrease in Child-Pugh score of at least 2 points, and the overall end-stage liver disease score decreased from 16±5 to 14±10 (mean ± SD, P<0.001) during the follow-up period. With ADV treatment, 67 patients (56.3%) had undetectable serum HBV DNA (detection limit, 0.5 pg/mL). Virologic breakthrough occurred in 38 patients (36.1%) and 9 patients had a suboptimal ADV response. The overall survival rate was 89.9% (107/119), and a suboptimal response to ADV treatment was associated with both no improvement in Child-Pugh score (≥2 points; P=0.001) and high mortality following ADV rescue therapy (P=0.012).

Conclusions

Three years of ADV treatment was effective and safe in decompensated patients with lamivudine-resistant HBV.

No association between the IL28B SNP and response to peginterferon plus ribavirin combination treatment in Korean chronic hepatitis C patients

BACKGROUND/AIMS

There are few available data regarding the association between the single nucleotide polymorphisms (SNPs) of the gene encoding interleukin 28B (IL28B) and a sustained virologic response (SVR) to peginterferon (PEG-IFN) plus ribavirin (RBV) therapy in Korean chronic hepatitis C patients.

METHODS

This was a retrospective cohort study of 156 patients with chronic hepatitis C virus (HCV) infection who received combination treatment of PEG-IFN plus RBV. Blood samples from these patients were analyzed to identify the IL28B SNPs at rs12979860, rs12980275, rs8099917, and rs8103142. Association analyses were performed to evaluate the relationships between each IL28B SNP and SVRs.

RESULTS

Seventy six patients with HCV genotype 1 and 80 with genotype non-1 were enrolled. The frequencies of rs12979860 CC and CT genotypes were 90.4% and 9.6%, respectively; those of rs12980275 AA and AG genotypes were 87.2% and 12.8%, respectively; those of rs8099917 TT and TG genotypes were 92.3% and 7.7%, respectively; and those of rs8103142 TT and CT genotypes were 90.4% and 9.6%, respectively. Among the patients with HCV genotype 1, the SVR rates were 69.7% and 80.0% for rs12979860 CC and CT, respectively (P=0.71). Among the HCV genotype non-1 patients, SVR rates were 88.0% and 100% for rs12979860 CC and CT (P=1.00), respectively.

CONCLUSIONS

Genotypes of the IL28B SNP that are known to be favorable were present in most of the Korean patients with chronic hepatitis C in this study. Moreover, the IL28B SNP did not influence the SVR rate in either the HCV genotype 1 or non-1 patients. Therefore, IL28B SNP analysis might be not useful for the initial assessment, prediction of treatment outcomes, or treatment decision-making of Korean chronic hepatitis C patients.

Clinical usefulness of endoscopic palliation in patients with biliary obstruction caused by hepatocellular carcinoma

BACKGROUND/AIMS

To evaluate the clinical usefulness of endoscopic biliary drainage (EBD) in patients with hepatocellular carcinoma (HCC).

METHODS

A total of 111 jaundiced patients underwent attempted EBD for relief of HCC-related biliary stricture at our hospital over a 5-year period and all were included in the intention-to-treat (ITT) analysis.

RESULTS

After an endoscopic attempt at drainage, 46 (41.4%) of the 111 patients achieved a favorable response. Biliary cannulation failed in 5 patients. Child-Pugh class C, portal vein thrombosis and severe hyperbilirubinemia were negatively correlated with a favorable EBD response. In the ITT population, 40 (87.0%) of the favorable responders received further treatment for HCC, >2 (3.1%) of the unfavorable responders (p < 0.001). The median survival time for ITT patients with and without a favorable response to EBD was 8.7 and 1.3 months, respectively (p < 0.001). Cox's model showed that a favorable EBD response was an independent predictor of longer survival (hazard ratio 0.20, p < 0.001).

CONCLUSIONS

For HCC patients with tumor-related biliary obstruction, predictors of effective endoscopic palliation of cholestasis were relatively mild hyperbilirubinemia and preserved liver function and intact portal vein flow. A favorable EBD response was associated with longer survival outcomes.

Catalytic upgrading of xylan over mesoporous Y catalyst

In-situ catalytic cracking of xylan, a model compound of hemicellulose, was carried out using pyrolysis-gas chromatography/mass spectrometry over mesoporous Y for the first time. Experiments were conducted at three different temperatures, 400 degrees C, 450 degrees C, and 500 degrees C, to investigate the effect of reaction temperature. Three different biomass-to-catalyst ratios, 1:1, 1:2, and 1:3, were tested at 500 degrees C to examine the effect of catalyst dose. In addition, the catalytic activity of mesoporous Y was compared with that of Al-MCM-41. The catalysts used were characterized by N2 adsorption-desorption, temperature programmed desorption of NH3, and X-ray diffraction. The main pyrolysis products of xylan were acids, hydrocarbons, phenolics, oxygenates, aromatics, and polycyclic aromatic hydrocarbons. Mesoporous Y, which has acid sites with larger quantity and stronger acidity than those of Al-MCM-41, was shown to enhance the quality of bio-oil to a larger extent, producing a larger quantity of high-value-added products, such as aromatics and furans.

Application of mesoporous Al-MCM-48 material to the conversion of lignin

Al-MCM-48 was applied to the catalytic pyrolysis of lignin for the first time. The pyrolysis reaction and in-situ product were analyzed by pyrolysis gas chromatography/mass spectrometry. The main products of the non-catalytic pyrolysis of lignin were phenols. The use of Al-MCM-48 increased the production of light phenols considerably. The yields of high-value-added compounds, such as hydrocarbons and aromatics, were also increased by catalytic upgrading. Al-MCM-48 is believed to promote cracking, aromatization and deoxygenation, such as decarbonylation. On the other hand, Si-MCM-48, which has no acid sites, showed lower deoxygenation efficiency than Al-MCM-48. Al-MCM-48 could be regenerated by calcining in air.

In situ catalytic pyrolysis of miscanthus over modified SBA-15 catalysts using Py-GC/MS

Various SBA-15-based catalysts, Si-SBA-15, Pt/Si-SBA-15, Al-SBA-15, and Pt/Al-SBA-15, were applied to the catalytic pyrolysis of miscanthus. Pt nanoparticles with three different sizes, 1.7 nm, 2.9 nm, and 7.1 nm, were used to synthesize Pt/Si-SBA-15 and Pt/Al-SBA-15. Pyrolysis-gas chromatography/mass spectrometry was used for the pyrolysis experiments. The catalysts were characterized by X-ray diffraction patterns, transmittance electron microscopy, N2 adsorption-desorption, and Brunaure-Emmett-Teller surface area. The product species distribution of pyrolysis of miscanthus was significantly affected by the acid property of the catalyst and the presence of Pt. In particular, Pt/Al-SBA-15, which has both acid sites and Pt, changed the product species distribution to the largest extent; the main products were phenolics and furans. The effect of Pt particle size on the species distribution of pyrolysis product was negligible.

Efficacy and safety of pegylated interferon-α2a in patients with lamivudine-resistant HBeAg-positive chronic hepatitis B

BACKGROUND

Lamivudine resistance develops in up to 80% of patients with chronic hepatitis B (CHB) after 5 years of treatment. Cross-resistance between nucleoside/nucleotide analogues limits management options in these patients. To investigate the role of pegylated interferon-α2a as rescue therapy in these patients, the efficacy and safety of pegylated interferon-α2a between treatment-naive patients and lamivudine-resistant patients with hepatitis B e antigen (HBeAg)-positive CHB were compared.

METHODS

A total of 150 HBeAg-positive CHB patients were stratified according to prior treatment. Lamivudine-resistant patients (n=64) and treatment-naive patients (n=86) received pegylated interferon-α2a once-weekly for 48 weeks and were followed-up for an additional 24 weeks. Primary end points were HBeAg loss and HBV DNA <100,000 copies/ml at end of follow-up.

RESULTS

A total of 65 (76%) treatment-naive patients and 49 (77%) lamivudine-resistant patients completed treatment and 24 weeks of follow-up. Rates of HBeAg loss were comparable at end of follow-up between treatment-naive patients and lamivudine-resistant patients (20.9% and 23.4%, respectively; P=0.8423). Similarly, rates of HBV DNA<100,000 copies/ml were comparable at end of follow-up between treatment-naive patients and lamivudine-resistant patients (20.9% and 21.9%, respectively; P=1.000). There was no statistically significant difference in alanine aminotransferase normalization rates between treatment-naive patients and lamivudine-resistant patients (36.0% and 29.7%, respectively; P=0.4848). A total of one patient in each group achieved hepatitis B surface antigen (HBsAg) loss and seroconversion. The most common adverse events were those known to occur with pegylated interferon-α2a therapy, and safety profiles were similar between both patient populations.

CONCLUSIONS

Pegylated interferon-α2a may be effective as a rescue therapy in patients with lamivudine-resistant HBeAg-positive CHB.

Randomized trial of the virologic response during up to two years of entecavir-adefovir combination therapy in multiple-drug-refractory chronic hepatitis B virus patients

A 1-year trial with entecavir plus adefovir resulted in a rate of virological response (VR) higher than that seen with lamivudine plus adefovir in multiple-drug-refractory chronic hepatitis B (CHB) patients. This extension study enrolled 89 of 90 patients who completed a 52-week randomized trial comparing treatment with entecavir plus adefovir (EA) to treatment with lamivudine plus adefovir (LA). At the baseline of the original study, all patients had lamivudine-resistant hepatitis B virus (HBV) and serum HBV DNA > 2,000 IU/ml despite prior lamivudine plus adefovir therapy. Of the 89 enrolled patients, 45 initially randomized to receive entecavir plus adefovir and the other 44 randomized to receive lamivudine plus adefovir received entecavir plus adefovir for an additional 52 weeks (EA-EA and LA-EA, respectively). The proportions of patients with a VR (serum HBV DNA < 60 IU/ml) gradually increased in both groups and were comparable at week 104 (42.2% in the EA-EA group and 34.1% in the LA-EA group; P = 0.51). The mean reductions in serum HBV DNA from baseline in the two groups were similar (-2.8 log10 IU/ml and -2.8 log10 IU/ml, respectively; P = 0.87). At week 104, the number of patients who retained the preexisting HBV mutants resistant to adefovir or entecavir had decreased from 8 to 2 in the EA-EA group and from 15 to 6 in the LA-EA group (P = 0.27). Both study groups had favorable safety profiles. In conclusion, up to 104 weeks of entecavir plus adefovir treatment was associated with a progressive VR, a decrease of levels of preexisting drug-resistant mutants, and no selection for additional resistance mutants of HBV in multiple-drug-refractory CHB patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01023217.).

Catalytic fast pyrolysis of lignin over mesoporous Y zeolite using Py-GC/MS

The catalytic pyrolysis of lignin was carried out at 500 degrees C using pyrolysis gas chromatography/mass spectrometry. In-situ vapor cracking method, in which the vapor-phase products from the noncatalytic pyrolysis step were catalytically upgraded in the second step, was used. Mesoporous Y zeolite, which was synthesized from commercial zeolite Y (CBV720) using the pseudomorphic synthesis method, was used for the catalytic pyrolysis of lignin for the first time. Further, a representative mesoporous material, Al-MCM-41, was applied for the catalytic pyrolysis of lignin. The main products of the non-catalytic pyrolysis of lignin were phenolic compounds because lignin mainly comprises phenylpropane units. Catalytic upgrading of the non-catalytic pyrolysis products resulted in increased yields of low-molecular-mass phenolics, mono aromatics, and poly aromatic hydrocarbons (PAHs). The production of mono aromatics and PAHs was enhanced remarkably when the more acidic mesoporous Y zeolite was used. Conversely, the yield-of alkoxy phenolics was higher when the less acidic Al-MCM-41 was used. With increasing mesoporous Y/lignin ratio, the yield of total phenolics decreased and that of light phenolics increased. The yields of mono aromatics and PAHs increased sharply with increasing mesoporous Y/lignin ratio.

A nationwide seroepidemiology of hepatitis C virus infection in South Korea

BACKGROUND & AIMS

The aim of this study was to reveal nationwide seroprevalence of HCV infection in South Korea by a large-scale survey.

METHODS

From January to December 2009, a total of 291 314 adults underwent health check-up in 29 centres nationwide. The data concerning anti-HCV antibody and biochemical tests were obtained from all participants. Among subjects with positive anti-HCV, such data as HCV RNA, genotypes and treatment detail were additionally analysed.

RESULTS

Using an estimated 2009 population of Korea, the age, sex and area-adjusted anti-HCV positive rate was 0.78%. Anti-HCV prevalence in female patients (0.83%) was higher than that in male patients (0.75%). Gradual increase in anti-HCV positivity was observed, from 0.34% in those aged 20-29 years to 2.31% in those >70 years. The age- and sex-adjusted anti-HCV prevalence varied in different areas, being higher in Busan and Jeonnam (1.53-2.07%), mid-level in Seoul and surrounding districts (0.50-0.61%) and lower in Jeju (0.23%). The comparative analysis of laboratory variables between anti-HCV (+) and anti-HCV (-) group revealed significantly higher levels of alanine aminotransferase and lower levels of serum lipids in anti-HCV (+) group. Among 1 718 anti-HCV positive subjects, serum HCV RNA was measured only in 478 people, of whom 268 (56.1%) patients had detectable HCV RNA in serum. Among 50 patients for whom assessment of response to antiviral therapy was feasible, overall sustained virological response was achieved in 84% of patients.

CONCLUSION

The prevalence of HCV infection is low in South Korea. Studies to analyse risk factors are warranted to reduce HCV infection.

High effectiveness of peginterferon alfa-2a plus ribavirin therapy in Korean patients with chronic hepatitis C in clinical practice

Background/Aims

Identifying the impact of a patient's ethnicity on treatment responses in clinical practice may assist in providing individualized treatment regimens for chronic hepatitis C (CHC). The effectiveness of standard peginterferon plus ribavirin therapy and the need for triple combination therapy with protease inhibitors in Koreans remain matters of debate. These issues were investigated in the present study.

Methods

The clinical data of 272 treatment-naïve Korean CHC patients who were treated in a community-based clinical trial (Clinical Trial group; n=51) and in clinical practice (Cohort group; n=221), were analyzed and compared. All were treated with standard protocols of peginterferon alfa-2a plus ribavirin therapy.

Results

For patients with hepatitis C virus (HCV) genotype 1, the sustained virological response (SVR) rates in the Clinical Trial and Cohort groups were 81% (21/26) and 55% (58/106), respectively, by intention-to-treat (ITT) analysis (P=0.02), and 100% (13/13) and 80% (32/40), respectively, in treatment-adherent patients (P=0.18). For patients with HCV genotype 2, the SVR rates in these two groups were 96% (24/25) and 88% (101/115), respectively, by ITT analysis (P=0.31). Adherence and treatment duration were independent predictors of SVR for genotypes 1 and 2, respectively (P<0.01 for each). Korean patients with CHC achieved high SVR rates with peginterferon alfa-2a plus ribavirin in both the clinical trial and clinical practice settings.

Conclusions

Measures to raise adherence to standard therapy in clinical practice may improve the SVR rates in these patients as effectively as adding protease inhibitors, thus obviating the need for the latter.

Mitochondrial swelling and microtubule depolymerization are associated with energy depletion in axon degeneration

Although mitochondrial dysfunction is intimately related to axonal degeneration following nerve injury, the molecular mechanisms of mitochondrial swelling and its mechanistic relation to axonal degeneration are largely unknown. Previous studies have demonstrated that axonal degeneration in the injured peripheral nerves shows two morphologically distinct phases: (1) A latency period (∼24h), in which the morphology of axonal cytoskeletons seems unchanged, followed by (2) an execution period (36-48h), which shows a catastrophic granular degeneration of most axonal structures in rodent axons. In the present study, we found that, in the sciatic nerve axotomy model, energy failure and microtubule depolymerization occurred during the latency period whereas mitochondrial swelling and neurofilament degradation started in the execution period. The energy repletion with NAD or an NAD/pyruvate mixture inhibited microtubule depolymerization, mitochondrial swelling and axonal degeneration in transected sciatic nerve axons. In addition, microtubule perturbing agents enhanced axonal degeneration and mitochondrial swelling. Extracellular calcium chelation did not affect energy failure, microtubule depolymerization or mitochondrial swelling, but it did prevent neurofilament degradation. These findings suggest that an early disturbance in energy dynamics regardless of mitochondrial swelling might be a key trigger for the initiation of axonal degeneration and that extracellular calcium influx is a late effector for neurofilament degradation.

Entecavir plus adefovir combination treatment for chronic hepatitis B patients after failure of nucleoside/nucleotide analogues

BACKGROUND

The combination of entecavir, a nucleoside analogue, and adefovir, a nucleotide analogue, would be a promising salvage treatment for chronic hepatitis B (CHB) patients who fail nucleoside/nucleotide analogue (NA) regimens.

METHODS

A total of 89 CHB patients who had failed NA regimens and were treated with entecavir plus adefovir combination for at least 12 months were included.

RESULTS

Mean baseline HBV DNA of patients was 6.16 ±1.44 log(10) IU/ml. Patients were classed by the number of previously failed NAs; 1 NA (lamivudine; n=15; Group 1), 2 NAs (lamivudine and either adefovir or entecavir; n=39; Group 2) and 3 NAs (lamivudine, adefovir and entecavir; n=35; Group 3). After 12 months of treatment, the mean reduction in HBV DNA was greater in Group 1 than in Group 2 or 3 (-5.81 ±1.71, -3.20 ±1.36 and -2.93 ±1.56 log(10) IU/ml, respectively; P<0.01). The rates of virological response (HBV DNA<2,000 IU/ml) were 100%, 79.5% and 34.3% (P<0.01), and the rates of complete virological response (HBV DNA<60 IU/ml) were 53.3%, 25.6% and 14.3% in Group 1, 2 and 3, respectively (P<0.01) at 12 months. Higher baseline HBV DNA (odds ratio =0.59; P=0.02) and increasing number of previously failed NAs (P<0.01) were independently associated with a lower rate of complete virological response at 12 months.

CONCLUSIONS

Entecavir plus adefovir combination treatment was effective in achieving virological response in CHB patients after failure of NAs. However, its effect progressively decreased as the number of previously failed NAs increased.