Development and validation of a noninvasive prediction model for significant hepatic liver fibrosis in Chinese patients with autoimmune hepatitis.

INTRODUCTION AND OBJECTIVES: Autoimmune hepatitis (AIH) is a prevalent noninfectious liver disease. However, there is currently a lack of noninvasive tests appropriate for evaluating liver fibrosis in AIH patients. The objective of this study was to develop and validate a predictive model for noninvasive assessment of significant liver fibrosis (S ≥ 2) in patients to provide a reliable method for evaluating liver fibrosis in individuals with AIH. MATERIALS AND METHODS: The clinical data of 374 AIH patients were analyzed. A prediction model was established through logistic regression in the training set, and bootstrap method was used to validate the models internally. In addition, the clinical data of 109 AIH patients were collected for external verification of the model.The model was expressed as a nomogram, and area under the curve (AUC) of the receiver operating characteristic (ROC), calibration curve, and decision curve analysis were used to evaluate the accuracy of the prediction model. RESULTS: Logistic regression analysis revealed that age, platelet count (PLT), and the A/G ratio were identified as independent risk factors for liver fibrosis in AIH patients (P < 0.05). The diagnostic model that was composed of age, PLT and A/G was superior to APRI and FIB-4 in both the internal validation (0.872, 95%CI: 0.819-0.924) and external validation (0.829, 95%CI: 0.753-0.904). CONCLUSIONS: Our predictive model can predict significant liver fibrosis in AIH patients more accurately, simply, and noninvasively.

Programmable Physical Properties of Freestanding Chitosan Membranes Electrofabricated in Microfluidics.

Microfluidic-integrated freestanding membranes with suitable biocompatibility and tunable physicochemical properties are in high demand for a wide range of life science and biological studies. However, there is a lack of facile and rapid methods to integrate such versatile membranes into microfluidics. A recently invented interfacial electrofabrication of chitosan membranes offers an in-situ membrane integration strategy that is flexible, controllable, simple, and biologically friendly. In this follow-up study, we explored the ability to program the physical properties of these chitosan membranes by varying the electrofabrication conditions (e.g., applied voltage and pH of alginate). We found a strong association between membrane growth rate, properties, and fabrication parameters: high electrical stimuli and pH of alginate resulted in high optical retardance and low permeability, and vice versa. This suggests that the molecular alignment and density of electrofabricated chitosan membranes could be actively tailored according to application needs. Lastly, we demonstrated that this interfacial electrofabrication could easily be expanded to produce chitosan membrane arrays with higher uniformity than the previously well-established flow assembly method. This study demonstrates the tunability of the electrofabricated membranes' properties and functionality, thus expanding the utility of such membranes for broader applications in the future.

Probing mutual interactions between Pseudomonas aeruginosa and Candida albicans in a biofabricated membrane-based microfluidic platform.

Microbes are typically found in multi-species (polymicrobial) communities. Cooperative and competitive interactions between species, mediated by diffusible factors and physical contact, leads to highly dynamic communities that undergo changes in composition diversity and size. Infections can be more severe or more difficult to treat when caused by multiple species. Interactions between species can improve the ability of one or more species to tolerate anti-microbial treatments and host defenses. Pseudomonas aeruginosa (Pa), a ubiquitous bacterium, and the opportunistic pathogenic yeast, Candida albicans (Ca), are frequently found together in cystic fibrosis lung infections and wound infections. While significant progress has been made in determining interactions between Pa and Ca, there are still important questions that remain unanswered. Here, we probe the mutual interactions between Pa and Ca in a custom-made microfluidic device using biopolymer chitosan membranes that support cross-species communication. By assembling microbes in physically separated, chemically communicating populations or bringing into direct interactions in a mixed culture, in situ polymicrobial growth and biofilm morphology were qualitatively characterized and quantified. Our work reveals new dynamic details of their mutual interactions including cooperation, competition, invasion, and biofilm formation. The membrane-based microfluidic platform can be further developed to understand the polymicrobial interactions within a controlled interactive microenvironment to improve microbial infection prevention and treatment.

Bacterial chemotaxis in static gradients quantified in a biopolymer membrane-integrated microfluidic platform.

Chemotaxis is a fundamental bacterial response mechanism to changes in chemical gradients of specific molecules known as chemoattractant or chemorepellent. The advancement of biological platforms for bacterial chemotaxis research is of significant interest for a wide range of biological and environmental studies. Many microfluidic devices have been developed for its study, but challenges still remain that can obscure analysis. For example, cell migration can be compromised by flow-induced shear stress, and bacterial motility can be impaired by nonspecific cell adhesion to microchannels. Also, devices can be complicated, expensive, and hard to assemble. We address these issues with a three-channel microfluidic platform integrated with natural biopolymer membranes that are assembled in situ. This provides several unique attributes. First, a static, steady and robust chemoattractant gradient was generated and maintained. Second, because the assembly incorporates assembly pillars, the assembled membrane arrays connecting nearby pillars can be created longer than the viewing window, enabling a wide 2D area for study. Third, the in situ assembled biopolymer membranes minimize pressure and/or chemiosmotic gradients that could induce flow and obscure chemotaxis study. Finally, nonspecific cell adhesion is avoided by priming the polydimethylsiloxane (PDMS) microchannel surfaces with Pluronic F-127. We demonstrated chemotactic migration of Escherichia coli as well as Pseudomonas aeruginosa under well-controlled easy-to-assemble glucose gradients. We characterized motility using the chemotaxis partition coefficient (CPC) and chemotaxis migration coefficient (CMC) and found our results consistent with other reports. Further, random walk trajectories of individual cells in simple bright field images were conveniently tracked and presented in rose plots. Velocities were calculated, again in agreement with previous literature. We believe the biopolymer membrane-integrated platform represents a facile and convenient system for robust quantitative assessment of cellular motility in response to various chemical cues.

Association between type 2 diabetes status and prevalence of liver steatosis and fibrosis among adults aged ≥ 40 years.

BACKGROUND: Type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease frequently coexist and share pathophysiological manifestations. This study aimed to explore the association between T2DM status and prevalence of liver steatosis and fibrosis, identified using the controlled attenuation parameter and liver stiffness measurement attained via liver ultrasound transient elastography. METHODS: This was a cross-sectional analysis of data collected in the National Health and Nutrition Examination Survey for 2017-2018. Multivariable logistic regression model was used to evaluate the association between T2DM and prevalence of liver steatosis and fibrosis. Subgroup analyses, stratified by sex age, race, and body mass index (BMI), were further performed. RESULTS: Of the 2,780 participants aged ≥ 40 years enrolled, 749 had T2DM, and 2,031 did not. After adjustment for potential confounders, T2DM was associated with a higher prevalence of liver steatosis (OR = 1.7, 95% CI, 1.3-2.1). This T2DM-related prevalence was higher among women (OR = 1.8, 95% CI, 1.3-2.5) and in the non-Hispanic Black (OR = 1.8, 95% CI, 1.1-3.0), other race (OR = 1.9, 95% CI, 1.2-3.0), and BMI < 25 kg/m2 (OR = 2.0, 95% CI, 1.1-3.8) groups. T2DM was also associated with a significantly higher prevalence of fibrosis (OR = 2.0, 95% CI, 1.5-2.7), with this association being more prominent for the other race (OR = 2.9, 95% CI, 1.5-5.5) and BMI < 25 kg/m2 (OR = 3.3, 95% CI: 1.3-8.8) groups. CONCLUSIONS: Our findings indicated a positive association between T2DM status and prevalence of hepatic steatosis and fibrosis. This association was more prominent for individuals with a BMI < 25 kg/m2 and was influenced by race-specific effects.

LncRNA KCNQ1OT1 activated by c-Myc promotes cell proliferation via interacting with FUS to stabilize MAP3K1 in acute promyelocytic leukemia.

Uncontrolled proliferation is the hallmark of cancer cells. Previous studies mainly focused on the role of protein-coding genes in cancer cell proliferation. Emerging evidence showed that long non-coding RNAs (lncRNAs) also play critical roles in cancer cell proliferation and growth. LncRNA KCNQ1OT1 is found to contribute to carcinogenesis, but its role in acute promyelocytic leukemia (APL) is unclear. In this study, by analyzing data from Gene Expression Omnibus, The Cancer Genome Atlas database and our clinical samples, we found that KCNQ1OT1 was selectively highly expressed in APL. Functional assays demonstrated that knockdown of KCNQ1OT1 reduced APL cell proliferation and increased apoptosis. Further evidence showed that KCNQ1OT1 was mainly located in the cytoplasm of APL patient-derived NB4 cells and APL patient bone marrow samples. Mechanistically, KCNQ1OT1 bound to RNA binding protein FUS, and silencing either KCNQ1OT1 or FUS reduced the expression level and stability of MAP3K1 mRNA. Whereas KCNQ1OT1 and FUS did not affect each other. Importantly, knockdown of MAP3K1 impaired APL cell proliferation. Finally, c-Myc transactivated KCNQ1OT1 in APL cells through binding to its promoter while knockdown of c-Myc decreased KCNQ1OT1 expression. Our results not only revealed that c-Myc transactivated KCNQ1OT1 and upregulated KCNQ1OT1 promoted APL cell proliferation, but also demonstrated that KCNQ1OT1 bound to FUS to synergistically stabilize MAP3K1 mRNA, thus facilitating APL cell proliferation. This study established a previously unidentified role of KCNQ1OT1 in the development of APL, and KCNQ1OT1 may serve as a potential therapeutic target for APL.

C/EBPα is indispensable for PML/RARα-mediated suppression of long non-coding RNA NEAT1 in acute promyelocytic leukemia cells.

Better understanding of the transcriptional regulatory network in acute promyelocytic leukemia (APL) cells is critical to illustrate the pathogenesis of other types of acute myeloid leukemia. Previous studies have primarily focused on the retinoic acid signaling pathway and how it is interfered with by promyelocytic leukemia/retinoic acid receptor-α (PML/RARα) fusion protein. However, this hardly explains how APL cells are blocked at the promyelocytic stage. Here, we demonstrated that C/EBPα bound and transactivated the promoter of long non-coding RNA NEAT1, an essential element for terminal differentiation of APL cells, through C/EBP binding sites. More importantly, PML/RARα repressed C/EBPα-mediated transactivation of NEAT1 through binding to NEAT1 promoter. Consistently, mutation of the C/EBP sites or deletion of retinoic acid responsive elements (RAREs) and RARE half motifs abrogated the PML/RARα-mediated repression. Moreover, silencing of C/EBPα attenuated ATRA-induced NEAT1 upregulation and APL cell differentiation. Finally, simultaneous knockdown of C/EBPα and C/EBPß reduces ATRA-induced upregulation of C/EBPε and dramatically impaired NEAT1 activation and APL cell differentiation. In sum, C/EBPα binds and transactivates NEAT1 whereas PML/RARα represses this process. This study describes an essential role for C/EBPα in PML/RARα-mediated repression of NEAT1 and suggests that PML/RARα could contribute to the pathogenesis of APL through suppressing C/EBPα targets.

Flow-assembled chitosan membranes in microfluidics: recent advances and applications.

The integration of membranes in microfluidic devices has been extensively exploited for various chemical engineering and bioengineering applications over the past few decades. To augment the applicability of membrane-integrated microfluidic platforms for biomedical and tissue engineering studies, a biologically friendly fabrication process with naturally occurring materials is highly desired. The in situ preparation of membranes involving interfacial reactions between parallel laminar flows in microfluidic networks, known as the flow-assembly technique, is one of the most biocompatible approaches. Membranes of many types with flexible geometries have been successfully assembled inside complex microchannels using this facile and versatile flow-assembly approach. Chitosan is a naturally abundant polysaccharide known for its pronounced biocompatibility, biodegradability, good mechanical stability, ease of modification and processing, and film-forming ability under near-physiological conditions. Chitosan membranes assembled by flows in microfluidics are freestanding, robust, semipermeable, and well-aligned in microstructure, and show high affinity to bioactive reagents and biological components (e.g. biomolecules, nanoparticles, or cells) that provide facile biological functionalization of microdevices. Here, we discuss the recent developments and optimizations in the flow-assembly of chitosan membranes and chitosan-based membranes in microfluidics. Furthermore, we recapitulate the applications of the chitosan membrane-integrated microfluidic platforms dedicated to biology, biochemistry, and drug release fields, and envision the future developments of this important platform with versatile functions.

Interfacial Electrofabrication of Freestanding Biopolymer Membranes with Distal Electrodes.

Using electrical signals to guide materials' deposition has a long-standing history in metal coating, microchip fabrication, and the integration of organics with devices. In electrodeposition, however, the conductive materials can be deposited only onto the electrode surfaces. Here, an innovative process is presented to electrofabricate freestanding biopolymer membranes at the interface of electrolytes without any supporting electrodes at the fabrication site. Chitosan, a derivative from the naturally abundant biopolymer chitin, has been broadly explored in electrodeposition for integrating biological entities onto microfabricated devices. It is widely believed that the pH gradients generated at the cathode deprotonate the positively charged chitosan chains into a film on the cathode surface. The interfacial electrofabrication with pH indicators, however, demonstrated that the membrane growth was driven by the instantaneous flow of hydroxyl ions from the ambient alginate solution, rather than the slow propagation of pH gradients from the cathode surface. This interfacial electrofabrication produces freestanding membrane structures and can be expanded to other materials, which presents a new direction in using electrical signals for manufacturing.

Modulating the properties of flow-assembled chitosan membranes in microfluidics with glutaraldehyde crosslinking.

Flow-assembled chitosan membranes are robust and semipermeable hydrogel structures formed in microfluidic devices that have been used for important applications such as gradient generation and studying cell-cell signaling. One challenge, however, remains unresolved. When a polydimethylsiloxane (PDMS) microchannel with a flow-assembled, deprotonated chitosan membrane (DCM) is treated with anti-adhesion agents such as Pluronic F-127 to prevent biomolecular and cellular adsorption on PDMS, the interaction between DCM and PDMS is compromised and the DCM easily delaminates. To address this challenge, DCMs in microfluidics are crosslinked with glutaraldehyde to modulate their properties, and the altered properties of the glutaraldehyde treated chitosan membrane (GTCM) are investigated. First, the GTCM's acidic resistance was confirmed, its mechanical robustness against hydrostatic pressure was significantly improved, and it remained intact on PDMS after Pluronic treatment. Second, crystallization in DCM and GTCM was investigated with quantitative polarized light microscopy (qPLM), which revealed that GTCM's optical retardance and anisotropy were lower, implying less molecular alignment than in DCM. Finally, membrane permeability was tested with FITC-labeled dextran transport experiments, which showed that the transport across GTCM was slightly higher than that across DCM. Overall, glutaraldehyde-crosslinked chitosan membrane has better acidic resistance, higher strength under Pluronic treatment, and less molecular microalignment, while its semi-permeability is retained. This study demonstrates how glutaraldehyde crosslinking can be used to modify and improve biopolymer membrane properties for broader applications, such as in an acidic environment or when Pluronic passivation is needed.

Does the "Miracle Drug" of Environmental Governance Really Improve Air Quality? Evidence from China's System of Central Environmental Protection Inspections.

Central environmental protection inspections have completed their goal of full coverage of 31 provinces in China, and more than 17,000 officials have been held accountable. The media has evaluated the effectiveness of central environmental protection inspections using the notions of "instant results" and the "miracle drug of environmental governance." Can this approach effectively promote local environmental governance? This paper takes the treatment effect of central environmental protection inspections on air pollution as an example. Using the method of regression discontinuity, central environmental protection inspections are found to have a positive effect on the air quality index (AQI), but this effect is only short term and unsustainable. Additionally, there are inter-provincial differences. Judging from the research results on sub-contaminants, the treatment effect of central environmental protection inspections on air pollution is mainly reflected in PM10, PM2.5 and CO. Under the current situation in which PM10 and PM2.5 are the main assessment indexes, this phenomenon indicates that due to the political achievements and promotion of local officials and for reasons of accountability, it is more effective for the central government to conduct specific environmental assessments through local governments than to conduct central environmental protection inspections.

Anisotropic, Mesoporous Microfluidic Frameworks with Scalable, Aligned Cellulose Nanofibers.

Cellulose paper has been extensively used in microfluidic analytical devices because of its hydrophilic nature. However, cellulose is randomly packed in paper without any particular orientation or channels within the bulk of the material, necessitating a complicated design of hydrophilic microchannels to guide the liquid flow. Herein, we develop an anisotropic mesoporous microfluidic framework (named as white wood) with aligned cellulose nanofibers and inherent microchannels via a facile one-step delignification process from natural wood. The hydrophilic nature of the innate microchannels in white wood makes it ideal for application as a pump-free microfluidic chip, exhibiting a fast and anisotropic liquid and large solid particle (as demonstrated with carbon nanotubes) mass transport, with a high transport speed along the channel direction approximately five times faster than that perpendicular to the channel direction. The anisotropic mass transport is further exemplified in the fabrication of chitosan films with aligned microstructures and birefringence, formed by virtue of unidirectional capillary forces exerted by the microchannels. We envision that our anisotropic mesoporous framework can have great applications to pump-free microfluidics, and the simple preparation process will pave a new way for the development of microfluidic devices based on chemically modified wood.

Combination of dual serum fluorescence, AFP and hepatic function tests is valuable to identify HCC in AFP-elevated liver diseases.

Serum alpha-fetoprotein (AFP) levels elevated in benign liver diseases (BLD) represent a challenge in hepatocellular carcinoma (HCC) diagnosis. The present study aimed to develop a simple method to identify HCC in AFP-elevated liver diseases based on combining serum fluorescence and general clinical data. Serum specimens and clinical data were collected from 201 HCC and 117 BLD (41 liver cirrhosis, 76 chronic hepatitis) patients with abnormal serum AFP levels. Dual serum fluorescence (autofluorescence and cell-free DNA-related fluorescence) intensities were sequentially measured and expressed as 6 fluorescence indicators. The diagnostic value of these fluorescence and clinical data were evaluated alone and in combination by the area under receiver operating characteristic curve (AUROC). All fluorescence indicators significantly differed between HCC and BLD and some of them were more valuable for diagnosing HCC than AFP (AUROC 0.782-0.801 vs. 0.752). The diagnostic model established with fluorescence indicators, AFP, hepatic function tests and age showed that AUROC, sensitivity, specificity and accuracy were 0.958 (95% CI 0.936-0.979), 92.0%, 88.9% and 92.3%, respectively, and positive rates in AFP-negative, early and small HCCs were 73.8%, 81.6% and 74.3%, respectively. In conclusion, the combination of dual serum fluorescence, AFP, hepatic function tests and age is simple and valuable for identifying HCC in serum AFP-elevated liver diseases.

Recent Advances in Aptamers Targeting Immune System.

The immune system plays important role in protecting the organism by recognizing non-self molecules from pathogen such as bacteria, parasitic worms, and viruses. When the balance of the host defense system is disturbed, immunodeficiency, autoimmunity, and inflammation occur. Nucleic acid aptamers are short single-stranded DNA (ssDNA) or RNA ligands that interact with complementary molecules with high specificity and affinity. Aptamers that target the molecules involved in immune system to modulate their function have great potential to be explored as new diagnostic and therapeutic agents for immune disorders. This review summarizes recent advances in the development of aptamers targeting immune system. The selection of aptamers with superior chemical and biological characteristics will facilitate their application in the diagnosis and treatment of immune disorders.

Simple and robust diagnosis of early, small and AFP-negative primary hepatic carcinomas: an integrative approach of serum fluorescence and conventional blood tests.

The diagnosis of early, small and alpha-fetoprotein (AFP)-negative primary hepatic carcinomas (PHCs) remains a significant challenge. We developed a simple and robust approach to noninvasively detect these PHCs. A rapid, high-throughput and single-tube method was firstly developed to measure serum autofluorescence and cell-free DNA (cfDNA)-related fluorescence using a real-time PCR system, and both types of serum fluorescence were measured and routine laboratory data were collected in 1229 subjects, including 353 PHC patients, 331 liver cirrhosis (LC) patients, 213 chronic hepatitis (CH) patients and 332 normal controls (NC). The results showed that fluorescence indicators of PHC differed from those of NC, CH and LC to various extents, and all of them were not associated with age, gender, or AFP level. The logistic regression models established with the fluorescence indicators alone and combined with AFP, hepatic function tests and blood cell analyses were valuable for distinguishing early, small, AFP-negative and all PHC from LC, CH, NC and all non-PHC, with areas under the receiver operating characteristic curves 0.857-0.993 and diagnostic accuracies 80.2-97.7%. Conclusively, serum autofluorescence and cfDNA-related fluorescence are able to be rapidly and simultaneously measured by our simple method and valuable for diagnosing early, small and AFP-negative PHCs, especially integrating with AFP and conventional blood tests.

[Study on the Micro-FTIR Spectra of the Euhedral Faceted Polycrystalline Diamonds (EFPCDs) from Western Yangtze Craton and Its Geological Significance].

The results of Micro-FTIR spectra analysis of the euhedral faceted polycrystalline diamonds (EFPCDs) from the Western Yangtze Craton show that the EFPCDs are mostly IaAB type, the concentration of nitrogen.varies greatly from 25. 70- 358.35 µg x g(-1). Different nitrogen content distributes in different diamond grains or position in same sample. The C Center was not found in the samples and the conversion from A center to B center is incomplete, in the meanwhile, B% value concentrated in 40%. Thus, polycrystalline diamonds are not formed in the stage of nucleation but gathered together after formation of the individual diamond grains during the residence time in the mantle. And its formation environment is. more complex than the euhedral faceted polycrystalline diamonds from Mengyin kimberlite, the Eastern of North China Craton. The diamonds extremely possibly originated in the deep mantle from 160 to 180 km, reaching the depth of the core of the Yangtze Craton, at the same time it is close to the bottom of the lithosphere. The C-H bond of sp2 hybridization are conducive to the formation of platelets in diamonds. Meanwhile, its concentrations are generally higher than the C-H bond of sp3 hybridization in the samples.

The modulation of coagulation by aptamers: an up-to-date review.

Coagulation and anticoagulation system is kept in balance by the orchestrated action of a variety of biological factors, and the disruption of this balance leads to the risk of hemorrhage or thrombosis. Oligonucleotide aptamers are single-stranded DNA (ssDNA) or RNA ligands that are synthesized in vitro and bind to target molecules through dimensional structure with high specificity and affinity, and thus represent attractive candidates for the development of agents to maintain the balance of coagulation and anticoagulation. In this review, we summarize recent progress in aptamer-based application in the modulation of coagulation. The aptamers with specific chemical and biological characteristics have great potential to be explored as agents for the treatment of blood coagulation abnormalities.

[Study on the FTIR spectra of OH in olivines from mengyin kimberlite].

The results of FTIR spectra study of OH in olivines from Mengyin kimberlite show that there are more than 60 OH absorption peaks in the range of 3800-3000 cm(-1). We identified four major spectral features in the OH absorption bands of kimberlitic olivines. One is with nuOH in the range of 3800-3700 cm(-1), which is caused by the vapour of the room circumstance, and can not be regarded as intrinsic or non-intrinsic nuOH of the olivines. Another one is with nuOH in the range of 3710-3620 cm(-1), which belongs to three "water"-bearing minerals including serpentine, talc and Mg-bearing amphiboles, which is the non-intrinsic nuOH of the olivines. There is the possibility that H in hydrous minerals mainly entered into olivines during post-emplacement processes of the kimberlite magma. The third one is with nuOH in the range of 3620-3425 cm(-1), which originated from H occupying the Si-defect in the olivine structure, forming humite-like defects, and/or the defects that H occupies (Mg,Fe)-depletion, which is certainly attributed to the intrinsic nuOH of the olivines. In this case, H possibly entered into olivines following its immersion in the high temperature and rich fluid kimberlite magma in the mantle circumstance. The last one is with nuOH in the range of 3425-3000 cm(-1). In this area, nuOH is assigned to fluid inclusions of the olivines, and is the non-intrinsic nuOH of olivines. Fluid inclusions can enter into the olivines either during post-emplacement processes of the kimberlite magma or during the periods that olivines were formed in the mantle.

Lactic acidosis during telbivudine treatment for HBV: a case report and literature review.

All oral nucleoside analogues against hepatitis B virus, with an exception of telbivudine, have been reported causing lactic acidosis (LA). Here we report the first case of chronic hepatitis B developing severe refractory LA during telbivudine monotherapy. A 36-year-old man of Chinese origin received telbivudine antiviral treatment for chronic hepatitis B. After 11 mo of therapy, he developed anorexia, nausea, and vomiting with mild muscle weakness. The patient was found with elevated serum creatine phosphokinase up to 3683 U/L (upper limit of normal 170 U/L) and marked LA. LA did not resolve immediately following discontinuation of telbivudine. His condition began to improve after hemodialysis treatment for 16 times and usage of glucocorticosteroid. The patient fully recovered after 16 wk of treatment. This is the first documented case with severe LA caused by telbivudine monotherapy. Besides serum creatine phosphokinase, blood lactate level should also be closely monitored in patients receiving telbivudine.

Single-primer-limited amplification: a method to generate random single-stranded DNA sub-library for aptamer selection.

The amplification of a random single-stranded DNA (ssDNA) library by polymerase chain reaction (PCR) is a key step in each round of aptamer selection by systematic evolution of ligands by exponential enrichment (SELEX), but it can be impeded by the amplification of by-products due to the severely nonspecific hybridizations among various sequences in the PCR system. To amplify a random ssDNA library free from by-products, we developed a novel method termed single-primer-limited amplification (SPLA), which was initiated from the amplification of minus-stranded DNA (msDNA) of an ssDNA library with reverse primer limited to 5-fold molar quantity of the template, followed by the amplification of plus-stranded DNA (psDNA) of the msDNA with forward primer limited to 10-fold molar quantity of the template and recovery of psDNA by gel excision. We found that the amount of by-products increased with the increase of template amount and thermal cycle number. With the optimized template amount and thermal cycle, SPLA could amplify target ssDNA without detectable by-products and nonspecific products and could produce psDNA 16.1 times as much as that by asymmetric PCR. In conclusion, SPLA is a simple and feasible method to efficiently generate a random ssDNA sub-library for aptamer selection.