Reservoir Computing with Charge-Trap Memory Based on a MoS2 Channel for Neuromorphic Engineering

Novel memory devices are essential for developing low power, fast, and accurate in-memory computing and neuromorphic engineering concepts that can compete with the conventional complementary metal-oxide-semiconductor (CMOS) digital processors. 2D semiconductors provide a novel platform for advanced semiconductors with atomic thickness, low-current operation, and capability of 3D integration. This work presents a charge-trap memory (CTM) device with a MoS2 channel where memory operation arises, thanks to electron trapping/detrapping at interface states. Transistor operation, memory characteristics, and synaptic potentiation/depression for neuromorphic applications are demonstrated. The CTM device shows outstanding linearity of the potentiation by applied drain pulses of equal amplitude. Finally, pattern recognition is demonstrated by reservoir computing where the input pattern is applied as a stimulation of the MoS2 -based CTMs, while the output current after stimulation is processed by a feedforward readout network. The good accuracy, the low current operation, and the robustness to input random bit flip makes the CTM device a promising technology for future high-density neuromorphic computing concepts.

Full Control of Solid-State Electrolytes for Electrostatic Gating

Ionic gating is a powerful technique to realize field-effect transistors (FETs) enabling experiments not possible otherwise. So far, ionic gating has relied on the use of top electrolyte gates, which pose experimental constraints and make device fabrication complex. Promising results obtained recently in FETs based on solid-state electrolytes remain plagued by spurious phenomena of unknown origin, preventing proper transistor operation, and causing limited control and reproducibility. Here, a class of solid-state electrolytes for gating (Lithium-ion conducting glass-ceramics, LICGCs) is explored, the processes responsible for the spurious phenomena and irreproducible behavior are identified, and properly functioning transistors exhibiting high density ambipolar operation with gate capacitance of ≈ 20   -   50   µ F c m - 2 \[20{\bm{ - }}50\;\mu F c{m^{{\bm{ - }}2}}\] (depending on the polarity of the accumulated charges) are demonstrated. Using 2D semiconducting transition-metal dichalcogenides, the ability to implement ionic-gate spectroscopy to determine the semiconducting bandgap, and to accumulate electron densities above 10¹⁴ cm^-2 are demostrated, resulting in gate-induced superconductivity in MoS₂ multilayers. As LICGCs are implemented in a back-gate configuration, they leave the surface of the material exposed, enabling the use of surface-sensitive techniques (such as scanning tunneling microscopy and photoemission spectroscopy) impossible so far in ionic-gated devices. They also allow double ionic gated devices providing independent control of charge density and electric field.

Targeting de novo lipogenesis and the Lands cycle induces ferroptosis in KRAS-mutant lung cancer

Mutant KRAS (KM), the most common oncogene in lung cancer (LC), regulates fatty acid (FA) metabolism. However, the role of FA in LC tumorigenesis is still not sufficiently characterized. Here, we show that KMLC has a specific lipid profile, with high triacylglycerides and phosphatidylcholines (PC). We demonstrate that FASN, the rate-limiting enzyme in FA synthesis, while being dispensable in EGFR-mutant or wild-type KRAS LC, is required for the viability of KMLC cells. Integrating lipidomic, transcriptomic and functional analyses, we demonstrate that FASN provides saturated and monounsaturated FA to the Lands cycle, the process remodeling oxidized phospholipids, such as PC. Accordingly, blocking either FASN or the Lands cycle in KMLC, promotes ferroptosis, a reactive oxygen species (ROS)- and iron-dependent cell death, characterized by the intracellular accumulation of oxidation-prone PC. Our work indicates that KM dictates a dependency on newly synthesized FA to escape ferroptosis, establishing a targetable vulnerability in KMLC.

Fatty Acid Oxidation Mediated by Acyl-CoA Synthetase Long Chain 3 Is Required for Mutant KRAS Lung Tumorigenesis

KRAS is one of the most commonly mutated oncogenes in human cancer. Mutant KRAS aberrantly regulates metabolic networks. However, the contribution of cellular metabolism to mutant KRAS tumorigenesis is not completely understood. We report that mutant KRAS regulates intracellular fatty acid metabolism through Acyl-coenzyme A (CoA) synthetase long-chain family member 3 (ACSL3), which converts fatty acids into fatty Acyl-CoA esters, the substrates for lipid synthesis and β-oxidation. ACSL3 suppression is associated with depletion of cellular ATP and causes the death of lung cancer cells. Furthermore, mutant KRAS promotes the cellular uptake, retention, accumulation, and β-oxidation of fatty acids in lung cancer cells in an ACSL3-dependent manner. Finally, ACSL3 is essential for mutant KRAS lung cancer tumorigenesis in vivo and is highly expressed in human lung cancer. Our data demonstrate that mutant KRAS reprograms lipid homeostasis, establishing a metabolic requirement that could be exploited for therapeutic gain.

PIAS1 Promotes Lymphomagenesis through MYC Upregulation

The MYC proto-oncogene is a transcription factor implicated in a broad range of cancers. MYC is regulated by several post-translational modifications including SUMOylation, but the functional impact of this post-translational modification is still unclear. Here, we report that the SUMO E3 ligase PIAS1 SUMOylates MYC. We demonstrate that PIAS1 promotes, in a SUMOylation-dependent manner, MYC phosphorylation at serine 62 and dephosphorylation at threonine 58. These events reduce the MYC turnover, leading to increased transcriptional activity. Furthermore, we find that MYC is SUMOylated in primary B cell lymphomas and that PIAS1 is required for the viability of MYC-dependent B cell lymphoma cells as well as several cancer cell lines of epithelial origin. Finally, Pias1-null mice display endothelial defects reminiscent of Myc-null mice. Taken together, these results indicate that PIAS1 is a positive regulator of MYC.

Focal Adhesion Kinase Regulates the DNA Damage Response and Its Inhibition Radiosensitizes Mutant KRAS Lung Cancer

PURPOSE

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide due to the limited availability of effective therapeutic options. For instance, there are no effective strategies for NSCLCs that harbor mutant KRAS, the most commonly mutated oncogene in NSCLC. Thus, our purpose was to make progress toward the generation of a novel therapeutic strategy for NSCLC.

EXPERIMENTAL DESIGN

We characterized the effects of suppressing focal adhesion kinase (FAK) by RNA interference (RNAi), CRISPR/CAS9 gene editing or pharmacologic approaches in NSCLC cells and in tumor xenografts. In addition, we tested the effects of suppressing FAK in association with ionizing radiation (IR), a standard-of-care treatment modality.

RESULTS

FAK is a critical requirement of mutant KRAS NSCLC cells. With functional experiments, we also found that, in mutant KRAS NSCLC cells, FAK inhibition resulted in persistent DNA damage and susceptibility to exposure to IR. Accordingly, administration of IR to FAK-null tumor xenografts causes a profound antitumor effect in vivo CONCLUSIONS: FAK is a novel regulator of DNA damage repair in mutant KRAS NSCLC and its pharmacologic inhibition leads to radiosensitizing effects that could be beneficial in cancer therapy. Our results provide a framework for the rationale clinical testing of FAK inhibitors in NSCLC patients. Clin Cancer Res; 22(23); 5851-63. ©2016 AACR.

PIAS1-FAK Interaction Promotes the Survival and Progression of Non-Small Cell Lung Cancer

The sequence of genomic alterations acquired by cancer cells during tumor progression and metastasis is poorly understood. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that integrates cytoskeleton remodeling, mitogenic signaling and cell survival. FAK has previously been reported to undergo nuclear localization during cell migration, cell differentiation and apoptosis. However, the mechanism behind FAK nuclear accumulation and its contribution to tumor progression has remained elusive. We report that amplification of FAK and the SUMO E3 ligase PIAS1 gene loci frequently co-occur in non-small cell lung cancer (NSCLC) cells, and that both gene products are enriched in a subset of primary NSCLCs. We demonstrate that endogenous FAK and PIAS1 proteins interact in the cytoplasm and the cell nucleus of NSCLC cells. Ectopic expression of PIAS1 promotes proteolytic cleavage of the FAK C-terminus, focal adhesion maturation and FAK nuclear localization. Silencing of PIAS1 deregulates focal adhesion turnover, increases susceptibility to apoptosis in vitro and impairs tumor xenograft formation in vivo. Nuclear FAK in turn stimulates gene transcription favoring DNA repair, cell metabolism and cytoskeleton regulation. Consistently, ablation of FAK by CRISPR/Cas9 editing, results in basal DNA damage, susceptibility to ionizing radiation and impaired oxidative phosphorylation. Our findings provide insight into a mechanism regulating FAK cytoplasm-nuclear distribution and demonstrate that FAK activity in the nucleus promotes NSCLC survival and progression by increasing cell-ECM interaction and DNA repair regulation.

Elevated expression of the miR-17-92 polycistron and miR-21 in hepadnavirus-associated hepatocellular carcinoma contributes to the malignant phenotype

Alterations in microRNA (miRNA) expression in both human and animal models have been linked to many forms of cancer. Such miRNAs, which act directly as repressors of gene expression, have been found to frequently reside in fragile sites and genomic regions associated with cancer. This study describes a miRNA signature for human primary hepatitis B virus-positive human hepatocellular carcinoma. Moreover, two known oncomiRs--miRNAs with known roles in cancer--the miR-17-92 polycistron and miR-21, exhibited increased expression in 100% of primary human and woodchuck hepatocellular carcinomas surveyed. To determine the importance of these miRNAs in tumorigenesis, an in vitro antisense oligonucleotide knockdown model was evaluated for its ability to reverse the malignant phenotype. Both in human and woodchuck HCC cell lines, separate treatments with antisense oligonucleotides specific for either the miR-17-92 polycistron (all six members) or miR-21 caused a 50% reduction in both hepatocyte proliferation and anchorage-independent growth. The combination of assays presented here supports a role for these miRNAs in the maintenance of the malignant transformation of hepatocytes.

Multi-miRNA hairpin method that improves gene knockdown efficiency and provides linked multi-gene knockdown

A number of natural microRNA (miRNA) hairpins have been found in clusters of multiple identical or different copies, suggesting that effects of miRNAs can be enhanced and multiple genes can be regulated together by encoding multiple miRNA hairpins in a single transcript. Here, we report a simple and effective artificial multi-hairpin method that stimulates production of mature 22-nucleotide small RNAs from modified miRNA hairpins, improves gene knockdown over single-hairpin constructs, and provides linked multi-gene knockdowns.

Hepatitis B virus DNA replication is coordinated by core protein serine phosphorylation and HBx expression

The hepatitis B virus (HBV) core protein forms the capsid of viral particles and is essential for viral genome DNA replication and maturation. The C terminus of core protein contains three serines at positions 155, 162, and 170, phosphorylation of which is important for viral DNA replication. We demonstrate that the phosphorylation of these serines is stimulated by the viral HBx protein, a regulatory protein that activates signal transduction pathways and viral replication. HBx is therefore shown to stimulate HBV replication by increasing core serine phosphorylation. Mutational, biochemical, and mixing studies of C-terminal core serine mutants demonstrate that multiple serine phosphorylations occur on the same core protein. Mutation of individual core protein serines is shown to inhibit HBV replication at distinct stages corresponding to encapsidation of viral pregenomic RNA, reverse transcription, and restriction to synthesis of specific DNA replicative intermediates. We therefore demonstrate that a primary target of HBV replication that is regulated by HBx protein corresponds to increased phosphorylation of the viral core protein. We also demonstrate that core phosphorylation mediated by HBx promotes sequential progression of viral replication through the assembly of capsids primed for different stages of DNA synthesis.

Development of a molecular-beacon assay to detect the G1896A precore mutation in hepatitis B virus-infected individuals

The 1896 precore (PC) mutation is the most frequent cause of hepatitis B virus e-antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infection. Detection of the 1896 PC mutation has application in studies monitoring antiviral therapy and the natural history of the disease. Identification of this mutation is usually performed by direct sequencing, which is both costly and laborious. The aim of this study was to develop a rapid, high-throughput assay to detect the 1896 PC mutation using real-time PCR and molecular-beacon technology. The assay was initially standardized on oligonucleotide targets and plasmids containing the wild-type (WT) and PC mutation and then tested on plasma samples from children with HBV DNA of >10(6) copies/ml. Nine individuals were HBeAg negative and suspected to harbor HBeAg mutations, while 12 children were HBeAg positive and selected as controls. Ninety percent (19 of 21) of plasma samples tested with molecular beacons were in complete agreement with sequencing results. The remaining 10% (2 of 21) of samples were identified as heterogeneous mixtures of WT and mutant virus by molecular beacons, though sequencing found only a homogeneous mutant in both cases. Overall, the 1896 PC mutation was detected by this assay in 55.5% of the children with HBeAg-negative infection. In summary, this assay is a rapid, sensitive, and specific technique that effectively discriminates WT from 1896 PC mutant HBV and may be useful in clinical and epidemiological studies.

Synthesis and aldose reductase inhibitory activity of benzoyl-amino acid derivatives

A series of N-(4-methoxy, 4-fluoro, 4-trifluoromethyl and 4-nitrobenzoyl)-L-amino acids was synthesized and their inhibitory activity towards bovine lens aldose reductase (ALR2) was tested.

Cloning and characterization of a novel hepatitis B virus x binding protein that inhibits viral replication

The hepatitis B virus and the mammalian hepadnavirus genomes encode for a short open reading frame called x. Expression of the protein product (HBx) appears necessary for establishment of natural infection. However, in vitro studies have suggested a multifunctional role for HBx as an indirect transcriptional transactivator of a variety of different viral and cellular promoters. Indeed, HBx has no known direct DNA binding properties but may interact with transcription factors as well as activate intracellular signaling pathways associated with cell growth. To further address the possible functional role of HBx in the life cycle of hepatitis B virus, we performed an analysis using the yeast two-hybrid system to screen a cDNA library derived from a hepatocellular carcinoma cell line with a HBx fusion bait in an attempt to identify cellular partners that may bind to and alter the biologic properties of HBx. A HBx-interacting protein that specifically complexes with the carboxy terminus of wild-type HBx was identified and designated XIP. This 9.6-kDa protein is capable of binding to HBx in vitro, and transient and stable expression in hepatocellular carcinoma cells abolishes the transactivation properties of HBx on luciferase constructs driven by AP-1 and endogenous hepatitis B virus enhancer/promoter elements. Investigation of the role of XIP in hepatitis B virus replication in differentiated hepatocellular carcinoma cells revealed that XIP expression reduces wild-type hepatitis B virus replication to levels observed following transfection with an HBx-minus virus. In contrast, the replication levels of the duck hepatitis B virus, a hepadnavirus that lacks the x open reading frame, were unchanged in the context of XIP expression. We propose that one of the physiologic functions of the cellular protein XIP is to negatively regulate HBx activity and thus to alter the replication life cycle of the virus.

Hepatitis B virus mutants associated with 3TC and famciclovir administration are replication defective

Hepatitis B virus (HBV) variant strains may develop during therapy for chronic infection with the nucleoside analog 2',3'-dideoxy-3'-thiacytidine (3TC). HBV mutants result from isoleucine (I) or valine (V) substitutions in the methionine (M) of the YMDD motif in the viral reverse-transcriptase catalytic domain. In addition, other mutations in the reverse-transcriptase "B domain" involving either a phenylalanine (F)-to-leucine (L) at amino acid 501 (F501L) or an L-to-M substitution at amino acid 515 (L515M) have been observed during 3TC and Famciclovir therapy as well. To determine the biologic consequences of these mutations on viral replication, variant viral genomes were constructed and transiently transfected into hepatocellular carcinoma (HCC) and HEK 293 human embryo kidney-derived cell lines. In transiently transfected HCC cells, the viruses bearing the YI/VDD or F501L mutations had greatly impaired replication as compared to wild-type virus, whereas the virus carrying the L515M substitution showed the least defect. Double mutants with the L515M substitution showed intermediate defect between the YI/VDD or F501L and the L515M single-mutant strains. In contrast, when transfected into HEK 293 cells, the viruses bearing the YI/VDD or L515M mutation replicated as wild-type. However, under conditions of deoxynucleotide depletion produced by hydroxyurea treatment of HEK 293 cells, all mutants but not the wild-type virus exhibited a reduced replication phenotype similar to that observed in HCC cells. In both HCC and HEK 293 cells, the mutant viruses carrying the F501L substitution showed a decreased pregenomic RNA encapsidation level, suggesting that the defect in HBV DNA synthesis occurs at the RNA packaging level. These findings show that 3TC and Famciclovir selected mutations alter the properties of the HBV reverse transcriptase, resulting in impaired viral replication within the cell.

Nucleic acid-based antiviral and gene therapy of chronic hepatitis B infection

Persistent hepatitis B virus (HBV) infection often leads to the development of chronic hepatitis, cirrhosis and hepatocellular carcinoma. There is a need to develop new antiviral approaches for the treatment of this disease. We have explored various nucleic acid-based strategies designed to inhibit HBV replication including: the use of antisense RNA and DNA constructs, DNA-based immunization techniques to stimulate broad-based cellular immune responses with particular emphasis on the generation of cytotoxic lymphocyte (CTL) activity to viral structural proteins, hammerhead ribozymes to cleave HBV pregenomic RNA in vitro and dominant negative HBV core mutant proteins as inhibitors of nucleocapsid formation within cells. In order to optimize these antiviral effects, various novel expression vectors have been developed to deliver such DNA constructs to cells. For example, adenoviral vectors carrying genes that encode for dominant negative proteins have been employed to transfect hepatocytes in vitro and in vivo. In addition, plasmid vectors have been produced to promote expression of HBV structural genes following injection into muscle cells as a means to stimulate the host's cellular and humoral immune response in the context of histocompatibility antigen (HLA) class I and II antigen presentation. These experimental approaches may have important implications for the generation of efficient antiviral effects during chronic HBV infection.

Biologic properties of hepatitis B viral genomes with mutations in the precore promoter and precore open reading frame

It is now well recognized that mutations in the hepatitis B virus (HBV) genome occur during the natural course of chronic viral infection. Regions of the viral genome that are frequently affected by such mutations, rearrangements, and/or deletions generally involve the precore promoter, precore, and core as well as the preS gene regions. However, little is known regarding the biologic consequences of these mutations on the functional properties of the variant viral strains with respect to effects on viral replication. In this study, we investigated the functional significance of precore promoter and precore gene mutations that reduce or abolish the synthesis of hepatitis B e antigen (HBeAg). We found that precore promoter mutations diminished the expression of HBeAg but did not affect the synthesis of pregenomic RNA. However, these precore mutations were associated with a modest increase in HBV replication. In contrast, a naturally occurring mutant that carries a termination codon in position 28 of the precore open reading frame demonstrated increased encapsidation of pregenomic mRNA into nucleocapsid particles. Consequently, this variant viral strain demonstrated a substantial increase in the level of viral replication compared to "wild-type" HBV and other precore promoter mutant viral strains. These studies suggest that substitutions in the precore promoter and precore gene not only alter the synthesis of HBeAg but also affect the level of viral replication.

The small envelope protein is required for secretion of a naturally occurring hepatitis B virus mutant with pre-S1 deleted

Naturally occurring deletions in the hepatitis B virus pre-S1 domain have been frequently found during persistent viral infection. In this study we have investigated the functional properties of a mutant viral genome that carries an in-frame deletion of 183 nucleotides in the pre-S1 region. This deletion removes the promoter of the small envelope gene. Transfection into human hepatocellular carcinoma cells of a replication-competent construct containing this deletion resulted in an increase of intermediate DNA replicative forms compared to those produced by wild-type hepatitis B virus. Northern blot analysis revealed that such cells lack the 2.1-kb transcripts encoding the small envelope protein and that hepatitis B surface antigen was absent as well. Furthermore, nucleocapsids containing the genome with pre-S1 deleted were not secreted, and the deleted large envelope protein was retained with the cytoplasm and exhibited a perinuclear pattern of distribution. However, coexpression with the small envelope protein was sufficient to restore virion secretion and to change the cellular distribution of the deleted large envelope protein. In addition, the creation of point mutations that prevent the synthesis of large or small envelope proteins also inhibited viral secretion and led to increased levels of hepatitis B virus intermediate replicative forms within the cell. These studies suggest that naturally occurring viral mutants with pre-S1 deletions involving the promoter region of the small envelope gene will generate a deleted large envelope protein that is retained in the endoplasmic reticulum, resulting in the accumulation of nucleocapsids containing viral DNA; transcomplementation with the wild-type small envelope protein will allow mutant virion secretion to occur.

Synthesis, antimicrobial and genotoxic properties of some benzoimidazole derivatives

A number of 1H-benzoimidazol-2-ylamine and of 1-methyl-1H-benzoimidazol-2-ylamine derivatives were synthesized and the crystal and molecular structure of N-[4-(2-amino-benzoimidazole-1-sulfonyl)-phenyl] acetamide was determined by X-ray diffraction analysis. The compounds obtained were investigated for antimicrobial and genotoxic activities.

Posttranscriptional regulation of hepatitis B virus replication by the precore protein

Hepadnaviruses encode two core-related open reading frames. One directs the synthesis of the p21 core protein, which subsequently becomes a structural component of the viral nucleocapsid. The other produces a p25 precore protein that is targeted by a signal peptide to a cell secretory pathway where N-terminal processing will create a p22 species. This molecule will be further modified at the C-terminal region to generate p17, and the truncated protein is secreted from the cell as hepatitis B e antigen (HBeAg). The function of the precore gene in the biology of hepadnaviruses is unknown. We found that ablation of the precore gene resulted in the generation of a hepatitis B virus (HBV) species with a high-replication-level phenotype. More important, expression in trans of physiologic levels of p25 restored viral replication to wild-type levels. Moreover, transient or stable overexpression of the precore gene resulted in striking inhibition of HBV replication. The molecular species responsible for this viral inhibitory effect was identified as the p22 nonsecreted HBeAg precursor protein. By sucrose gradient sedimentation analysis, we determined that expression of p22 leads to the formation of nucleocapsids similar to those made with wild-type p21 core protein. Immunoprecipitation experiments revealed that the p21 and p22 physically interact and form hybrid nucleocapsid structures devoid of pregenomic viral RNA. These experiments suggest that expression of the precore gene may be important in the regulation of HBV replication and describe a possible molecular mechanism(s) for this effect.

Use of dominant negative mutants of the hepadnaviral core protein as antiviral agents

Chronic hepatitis B virus (HBV) infection is a major cause of acute and chronic liver diseases. We have recently described HBV and woodchuck hepatitis virus (WHV) dominant negative (DN) core mutants that were capable of inhibiting wild-type viral replication by 95%. These mutants may represent a potent class of antiviral agents that act as "intracellular immunogens." To facilitate their potential use in animal model systems, we now have studied the duck HBV (DHBV) and placed the DN mutant constructs in recombinant retroviral and adenoviral expression vectors. Transient expression of the DHBV molecular equivalent of the WHV and HBV DN constructs inhibited wild-type DHBV replication by 98%. Recombinant retroviral and adenoviral vectors containing the HBV and DHBV DN complementary DNAs (cDNAs) were used to transiently and stably transduce hepatoma-derived cell lines constitutively expressing replicating wild-type virus. These investigations show that the DN core mutants were powerful inhibitors of HBV and DHBV replication when delivered intracellularly and appear as promising antiviral agents for gene therapy of persistent viral infection of the liver.

Recent advances in the molecular biology of hepatitis B virus

Hepatitis B virus (HBV) is an enveloped hepatotropic DNA virus. Acute and chronic HBV infection causes significant liver diseases such as acute hepatis, fulminant hepatitis and chronic active hepatitis that may lead to liver cirrhosis and the development of hepatocellular carcinoma. The use of molecular biological techniques has substantially improved our understanding of the HBV life cycle. In this review, we discuss recent advances that have contributed to a better understanding of HBV biology. Recent studies in the understanding of the life cycle of HBV such as viral entry, replication, transcriptional regulation, viral regulatory proteins, viral assembly and secretion, and nucleic acid based approaches to antiviral therapy will be emphasized. These advances in molecular biology and relationship to clinical disease will be instrumental in developing effective therapeutic approaches for the estimated 300 million individuals worldwide chronically infected with HBV.

Characterization of hepatitis B virus core mutants that inhibit viral replication

We have generated and functionally characterized dominant negative core protein variants of the hepadnaviruses to determine their effects on "wild type" viral replication. Plasmids expressing these constructs were introduced into hepatoma cell lines by transient transfection and effects on wild type woodchuck hepatitis virus (WHV) and hepatitis B virus (HBV) replication were evaluated by Southern blot analysis of purified viral core particles. WHV and HBV constructs expressing a truncated core protein fused in frame with the C-terminus of the small surface protein were found to inhibit viral replication by 90-95% due to disruption of the viral nucleocapsid assembly process and preventing encapsidation of pregenomic RNA. The antiviral effects were found to be specific for the targeted virus. These results demonstrate that mutants of hepadnaviral core protein may represent a novel class of antiviral agents.

Properties of hepatitis B virus pre-S1 deletion mutants

Deletion mutants of hepatitis B virus (HBV) pre-S proteins were detected in serum in 2 of 10 (20%) individuals with chronic hepatitis B infection following the initiation of interferon treatment. The size of these deletions was up to one-half of the entire pre-S1 region. In vivo, all HBV deletion mutants were found to coexist with a full-length "wild-type" viral genome. The functional properties of a HBV-deleted mutant were studied in detail and revealed a stop codon in the pre-S2 open reading frame in all 20 of the clones sequenced. Several of the deleted mutants produced low-level HBsAg in culture supernatants compared to wild-type virus due to a putative loss of transcription factor binding sites. Transfection experiments in human hepatoma cells (HuH-7) demonstrated that the polymerase gene function was not affected by the large pre-S1 deletions and mutant viral genomes were capable of replication. However, secretion of incapsidated mutant viral genomes was blocked in HuH-7 cells. Cotransfection studies with a plasmid expressing only the HBV pre-S1, pre-S2, and S proteins resulted in complete restoration of viral particle secretion. Our findings suggest that an in vivo trans-complementation phenomenon would have had to occur to permit secretion from the liver into serum of the nucleocapsids containing these deleted viral genomes.

Presence of HCV RNA in serum of asymptomatic blood donors involved in post-transfusion hepatitis (PTH)

To study the causes of residual posttransfusion hepatitis, serum from implicated donors was tested by PCR for the presence of HCV RNA. Of 20 anti HCV negative donors, 4 were HCV RNA positive and thus, infective. The results suggest that higher-level investigations are necessary for prospective donors who present blood enzyme abnormalities or other questionable characteristics.

Hepatitis B virus specific transcripts in peripheral blood mononuclear cells

We report on the analysis of HBV transcription in peripheral blood mononuclear cells of chronically infected patients by polymerase chain reaction amplification. Our results suggest that in these cells gene expression occurs either as pregenomic or subgenomic transcripts.

HCV RNA in serum of asymptomatic blood donors involved in post-transfusion hepatitis (PTH)

A group of blood donors involved in post-transfusion hepatitis was investigated for the presence of the anti-HCV antibody and of HCV RNA as a more direct infection marker. RNA was extracted from serum, reverse transcribed and amplified using primers which belonged to the non structural region. The amplified product of the PCR reaction was 582 base pairs. Seven (25.9%) of the 27 blood donors examined were found anti-HCV-positive by ELISA; five (71.4%) of these were HCV RNA positive. Among the 20 anti-HCV-negative blood donors, four (20.0%) were HCV RNA positive. ALT levels were below 45 UI/l in 18 donors, while the other nine had ALTs over the limit accepted for transfusion. The anti-HCV-negative HCV RNA-positive blood donors had normal ALTs. Our study offers a direct explanation for the substantial proportion of residual cases of anti-HCV-positive post-transfusion hepatitis and suggests the necessity of creating a register of blood donors who have at some time presented blood enzyme abnormalities and for whom second level investigations such as HCV RNA should be used.

Conserved core protein sequences in hepatitis B virus infected patients without anti-HBc

The absence of detectable anti-HBc antibodies in some hepatitis B virus (HBV) infected patients may be due to altered core-protein (HBc) sequences. To investigate this possibility we sequenced the pre-C/C-region of HBV isolated from 12 juvenile cancer patients who incurred a nosocomial infection of HBV during chemotherapy but did not develop anti-HBc antibodies or acute cytolytic episodes. The sequences demonstrated the highest sequence homology to the pre-C/C region of a previously cloned HBV genome (subtype ayw) and no deletions or striking mutations were detected. Up to 7 years after infection almost all the survivors developed low titers of anti-HBc antibodies but no clinical signs of hepatic damage. These results suggest that chemotherapy may induce a tolerance status to HBcAg, the most immunogenic HBV protein.

Hepatocellular carcinoma: risk factors other than HBV

The putative risk factors for hepatocellular carcinoma (HCC) are several, even in countries endemic for hepatitis B virus (HBV) infection. Cirrhosis characterizes more than 90% of HCC cases. The phases of inflammation, necrosis and regeneration, present for long periods in cirrhosis, might be most relevant in hepatocarcinogenesis. It is not clear what role is played by sex hormones while alcohol probably has a promoter role. Aflatoxins are known carcinogenins in the experimental animal: however it is difficult to evaluate the impact in human carcinogenesis due to the lack of reliable methods of measuring aflatoxin exposure in population studies. In conclusion, the aetiology of HCC is multifactorial and the main risk factor resides in the presence of underlying chronic liver disease.

Significance of anti-HBx antibodies in hepatitis B virus infection

Serological responses to hepatitis B virus-X determinants have been noted in human sera, but conflicting findings concerning the correlation of anti-HBx antibodies with different stages of hepatitis B virus infection or pathological sequelae have been reported. Using an adenovirus-based eukaryotic vector, the 17 kD X protein was efficiently expressed in 293 cells. Cellular extracts containing the eukaryotic X protein have been used to screen for anti-HBx antibodies by immunoblot analysis in a large panel of sera from patients affected by hepatitis B virus chronic hepatitis, hepatocellular carcinoma and acute viral hepatitis. Sera from 32 of 171 (19%) chronic hepatitis B virus patients were positive for anti-HBx antibodies. Only one of thirty-two (3%) HBsAg-negative, anti-HBs/anti-HBc-positive chronic hepatitis serum was anti-HBx positive. Very few sera from primary hepatocellular carcinoma patients showed positivity for anti-HBx (8 of 149 or 5%). Anti-HBx were also detected in 8 of 48 (17%) acute viral hepatitis patients. In the four cases that were followed up weekly, anti-HBx antibodies appeared 3 to 4 wk after the onset of the clinical signs. To compare the X protein expressed in eukaryotic and prokaryotic cells as a substrate for anti-HBx antibody detection, 171 sera were screened with HBx fusion proteins expressed in Escherichia coli. The prokaryotic cell extract test seems to be more sensitive. During the chronic phase of hepatitis B virus infection, the presence of anti-HBx antibodies detected with the eukaryotic cell extract correlates with the presence of well-established markers of ongoing viral replication: serum hepatitis B virus-DNA (p less than 0.001) and intrahepatic HBcAg expression (p less than 0.001).

Hepatitis B virus infection of peripheral blood mononuclear cells is common in acute and chronic hepatitis

Hepatitis B virus (HBV) infection of peripheral blood mononuclear cells (PBMCs) has been observed in all stages of liver disease. Thus far all information about the physical state of HBV in mononuclear blood cells comes from Southern blot analysis and in situ hybridization. In this study we focused our attention on the presence of HBV DNA sequences in PBMCs of 30 patients with acute type B hepatitis and 6 patients with chronic active hepatitis by utilizing both Southern blot analysis and the polymerase chain reaction (PCR). Southern blot analysis showed no HBV DNA sequences in PBMCs of the acute hepatitis patients, although the sensitivity of our method enabled us to detect as little as 1 pg of cloned HBV insert. As far as the chronic hepatitis patients are concerned Southern blot analysis revealed the presence of HBV DNA sequences in 5 out of 6 patients but intermittently at successive follow-up times. On the other hand we were able to demonstrate the presence of HBV related sequences in 14 out of 30 acute hepatitis patients (5 HBeAg positive, 9 antiHBe positive) and in all 6 chronic hepatitis patients by PCR. Our results indicate that the involvement of PBMCs with HBV during acute HBV infection occurs at a very low level, often below the detection limit of the Southern blot technique.

[Estrogen receptors in the human liver]

Human hepatic estrogen receptors (ER) were investigated in 17 healthy subjects (13 males and 4 females) and 70 patients with chronic liver disease (45 males and 25 females). Characterization of the estrogen binders in cytosol from human male liver showed two classes of binders, the first of them corresponding to estrogen receptor (Kd = 10(-10) M), and the second representing a low affinity binder (KD = 10(-8) M). Increased ER levels were found in males with chronic liver disease, patients with primary hepatic carcinoma (PHC) having about twice the levels of normal males. Normal females had basal values about three times higher than control males; during the progression of chronic liver disease, ER levels fell to arise again slowly so that, in PHC, values were about half of those in normal females. Prolonged alcohol abuse appeared to induce a marked increase in ER levels both in male and in female patients. The increase was maximal in patients who were still actively drinking and in those with histological signs of acute alcoholic hepatitis.

Detection of hepatitis B virus transcripts in patients with chronic liver disease

Hepatitis B virus (HBV) transcription was studied by Northern blot analysis on total cellular RNA purified from liver biopsies in 70 patients with chronic liver disease (24 HBsAg positive, 15 antiHBs and/or antiHBc positive, 31 HBV negative). No transcripts were found in the HBV negative and in the antiHBs and/or antiHBc positive patients. In the others, three major RNA species were identified: i. a 3.5 kb transcript corresponding to the RNA pregenome; ii. 2.4-2.1 kb transcript corresponding to the s and preS1 gene RNA; iii. lower molecular weight species. All three forms were present simultaneously only in patients with active viral replication, with a strict relation between the presence of the 3.5 kb RNA in the liver and serum HBV-DNA. In conclusion, Northern blot analysis can easily be performed to study viral replication and it can contribute to a better understanding of the molecular processes underlying HBV infection and leading to liver disease in man.

[HBV DNA in mononuclear cells of peripheral blood in acute hepatitis B: a comparative analysis of Southern blot and polymerase chain reaction (PCR)]

Hepatitis B virus (HBV) infection of peripheral blood mononuclear cells (PBMCs) has been observed in all stages of liver disease. The data available on acute hepatitis patients are limited. We therefore focused our attention on the presence of HBV DNA sequences in PMBCs of 30 patients with acute type B hepatitis. Southern Blot analysis showed no HBV sequences in PMBCs, although the sensitivity of our method enabled us to detect as low as 1 pg of cloned HBV insert. On the other hand, Polymerase Chain Reaction (PCR) demonstrated the presence of HBV related sequences in 14 out of 30 patients (5 HBeAg positive, 9 anti HBeAg positive). Our results indicate that the involvement of PMBCs with HBV during acute infection is not correlated with viral replication and occurs at a very low level, so that its detection by traditional Southern Blotting can prove ineffective.

Characterization of some parameters of non-specific immunity in dairy cattle (I)

The concentrations of serum protein and immunoglobulin, complement, lysozyme, serum bactericidal activity and blast transformation of peripheral blood lymphocytes were assessed in dairy cattle in different herds and age groups. The study aimed at defining fundamental aspects of non-specific defence under the field conditions, related to age/season/management influences. The observed differences in the expression of these parameters are discussed, with regard to their role in the immune defence of calves and their relation to colostrum uptake. The possible use of these parameters in the control of animal welfare is stressed and the possibility is put forward of predicting possible unfavourable interactions with environmental pathogens.

Sedative, anti-inflammatory and anti-diuretic effects induced in rats by essential oils of varieties of Anthemis nobilis: a comparative study

The pharmacological properties of essential oils obtained from two varieties of Anthemis nobilis was studied. The two varieties, named "white-headed" or double flowered and "yellow-headed", present considerable morphological differences and yield essential oils with different composition. These essential oils proved to possess interesting anti-inflammatory and sedative properties, especially that derived from the "White-headed" variety.

Ethanol-induced increase in cytosolic estrogen receptors in human male liver: a possible explanation for biochemical feminization in chronic liver disease due to alcohol

The hepatic cytosolic estrogen receptor content was measured in liver samples from patients with normal livers and from patients with nonalcoholic cirrhosis, alcoholic cirrhosis and alcoholic hepatitis. The estrogen receptor content of normal liver was 5.2 +/- 3.5 fmoles per mg of cytosolic protein. Levels which were not significantly different from this were found in the samples from patients with nonalcoholic cirrhosis (2.1 +/- 2.0 fmoles per mg of cytosolic protein). The cytosolic estrogen receptor content in the livers of patients with alcoholic cirrhosis who were abstaining was 4.2 +/- 3.6 fmoles per mg of cytosolic protein, but it increased to 10.4 +/- 4.9 fmoles per mg of protein in the livers of patients with alcoholic cirrhosis who were drinking, to 17.3 +/- 8.7 fmoles per mg of protein in the livers of patients with alcoholic hepatitis with cirrhosis and to 22.7 +/- 15.7 fmoles per mg of protein in the livers of patients with alcoholic hepatitis without cirrhosis. Alcohol abuse appeared, therefore, to induce an increase in the estrogen receptor content of human liver, especially in patients who were drinking and had histological evidence of acute liver damage (alcoholic hepatitis). The increase in hepatic estrogen receptor which we have observed may be involved in the molecular mechanisms underlying the feminization of the liver in alcoholic males.

Risk factors for hepatocellular carcinoma in Italy. Male sex, hepatitis B virus, non-A non-B infection, and alcohol

To investigate risk factors for hepatocellular carcinoma (HCC) in Italy--a country with medium (south: 5% to 10%) to low (north: 1% to 2%) incidence of hepatitis B virus (HBV) infection--we studied 646 consecutive patients: 58 chronic active hepatitis (CAH), 428 cirrhosis, and 160 HCC, 49% from Southern and 51% from Northern Italy. Hepatitis B surface antigen (HBsAg) was positive in 41.4% of the CAH, in 23.1% of cirrhotic patients, and in 26.2% of HCC. In the latter, HBV DNA assay increased the number of subjects with active HBV infection by about 12%. Alcohol abuse was evenly distributed in all three categories of HBV markers. Males were preferentially affected. The HCC was superimposed on cirrhosis in more than 90% of patients. Our data suggest that, in our epidemiologic setting, different factors (HBV, non-A, non-B agents, alcohol) may cooperate in the development of HCC, mainly through their potential for causing cirrhosis.

Risk factors for hepatocellular carcinoma in Italy. Male sex, hepatitis B virus, non-A non-B infection, and alcohol

To investigate risk factors for hepatocellular carcinoma (HCC) in Italy--a country with medium (south: 5% to 10%) to low (north: 1% to 2%) incidence of hepatitis B virus (HBV) infection--we studied 646 consecutive patients: 58 chronic active hepatitis (CAH), 428 cirrhosis, and 160 HCC, 49% from Southern and 51% from Northern Italy. Hepatitis B surface antigen (HBsAg) was positive in 41.4% of the CAH, in 23.1% of cirrhotic patients, and in 26.2% of HCC. In the latter, HBV DNA assay increased the number of subjects with active HBV infection by about 12%. Alcohol abuse was evenly distributed in all three categories of HBV markers. Males were preferentially affected. The HCC was superimposed on cirrhosis in more than 90% of patients. Our data suggest that, in our epidemiologic setting, different factors (HBV, non-A, non-B agents, alcohol) may cooperate in the development of HCC, mainly through their potential for causing cirrhosis.

Preparation and physicochemical properties of uracil derivatives with potential biological activity

The characterization of mono- and dimethylated 5-substituted uracils was re-examined. Analysis of their physicochemical properties (pKa, U.V., delta 1H-N.M.R.) affords insight into the structural characteristics of 5-substituted uracil alkylated at the ring nitrogens.

Safety and efficacy of foot-and-mouth disease vaccines containing endonuclease-inactivated virions

Inactivation of foot-and-mouth disease virus (FMDV) by means of virion-associated endonuclease was found to be suited to the production of safe and potent vaccines, which proved to be equal or better than those containing formaldehyde or ethyleneimine in guinea-pig potency tests. First order inactivation kinetics were regularly shown, with half life values which varied according to the different temperatures used. Inactivation brought about extensive degradation of FMDV RNA, while it did not adversely influence the integrity of critical viral epitopes on FMDV VP1.

Antimycotic action of alkyl derivatives of 5-(benzenesulfonamide)-1,2,3,4-tetrahydro-2-thioxo-4-pyrimidinon e

Several series of mono-, di- and trimethyl derivatives of N-(6-amino-1,2,3,4-tetrahydro-4-oxo-2-thioxo-5-pyrimidinyl)benzene sulfonamide substituted at the benzene ring (Z), were synthesized and studied spectrophotometrically. The spectral and physical data enabled the structures of the methyl derivatives obtained by methylating (Z) to be identified. When assayed biologically as antimycotics, a small percentage of the substances exhibited mild fungicide activity.