In Situ Prelithiation by Direct Integration of Lithium Mesh into Battery Cells

Silicon (Si)-based anodes are promising for next-generation lithium (Li)-ion batteries due to their high theoretical capacity (∼3600 mAh/g). However, they suffer quantities of capacity loss in the first cycle from initial solid electrolyte interphase (SEI) formation. Here, we present an in situ prelithiation method to directly integrate a Li metal mesh into the cell assembly. A series of Li meshes are designed as prelithiation reagents, which are applied to the Si anode in battery fabrication and spontaneously prelithiate Si with electrolyte addition. Various porosities of Li meshes tune prelithiation amounts to control the degree of prelithiation precisely. Besides, the patterned mesh design enhances the uniformity of prelithiation. With an optimized prelithiation amount, the in situ prelithiated Si-based full cell shows a constant >30% capacity improvement in 150 cycles. This work presents a facile prelithiation approach to improve battery performance.

Enhancement of Gene Editing and Base Editing with Therapeutic Ribonucleoproteins through In Vivo Delivery Based on Absorptive Silica Nanoconstruct

Key to the widespread and secure application of genome editing tools is the safe and effective delivery of multiple components of ribonucleoproteins (RNPs) into single cells, which remains a biological barrier to their clinical application. To overcome this issue, a robust RNP delivery platform based on a biocompatible sponge-like silica nanoconstruct (SN) for storing and directly delivering therapeutic RNPs, including Cas9 nuclease RNP (Cas9-RNP) and base editor RNP (BE-RNP) is designed. Compared with commercialized material such as lipid-based methods, up to 50-fold gene deletion and 10-fold base substitution efficiency is obtained with a low off-target efficiency by targeting various cells and genes. In particular, gene correction is successfully induced by SN-based delivery through intravenous injection in an in vivo solid-tumor model and through subretinal injection in mouse eye. Moreover, because of its low toxicity and high biodegradability, SN has negligible effect on cellular function of organs. As the engineered SN can overcome practical challenges associated with therapeutic RNP application, it is strongly expected this platform to be a modular RNPs delivery system, facilitating in vivo gene deletion and editing.

High-purity production and precise editing of DNA base editing ribonucleoproteins

Ribonucleoprotein (RNP) complex-mediated base editing is expected to be greatly beneficial because of its reduced off-target effects compared to plasmid- or viral vector-mediated gene editing, especially in therapeutic applications. However, production of recombinant cytosine base editors (CBEs) or adenine base editors (ABEs) with ample yield and high purity in bacterial systems is challenging. Here, we obtained highly purified CBE/ABE proteins from a human cell expression system and showed that CBE/ABE RNPs exhibited different editing patterns (i.e., less conversion ratio of multiple bases to single base) compared to plasmid-encoded CBE/ABE, mainly because of the limited life span of RNPs in cells. Furthermore, we found that off-target effects in both DNA and RNA were greatly reduced for ABE RNPs compared to plasmid-encoded ABE. We ultimately applied NG PAM-targetable ABE RNPs to in vivo gene correction in retinal degeneration 12 (rd12) model mice.

PE-Designer and PE-Analyzer: web-based design and analysis tools for CRISPR prime editing

Prime editing technology is capable of generating targeted insertions, deletions, and base conversions. However, the process of designing prime editing guide RNAs (pegRNAs), which contain a primer binding site and a reverse-transcription template at the 3′ end, is more complex than that for the single guide RNAs used with CRISPR nucleases or base editors. Furthermore, the assessment of high-throughput sequencing data after prime editors (PEs) have been employed should consider the unique feature of PEs; thus, pre-existing assessment tools cannot directly be adopted for PEs. Here, we present two user-friendly web-based tools for PEs, named PE-Designer and PE-Analyzer. PE-Designer, a dedicated tool for pegRNA selection, provides all possible target sequences, pegRNA extension sequences, and nicking guide RNA sequences together with useful information, and displays the results in an interactive image. PE-Analyzer, a dedicated tool for PE outcome analysis, accepts high-throughput sequencing data, summarizes mutation-related information in a table, and provides interactive graphs. PE-Analyzer was mainly written using JavaScript so that it can analyze several data sets without requiring that huge sequencing data (>100MB) be uploaded to the server, reducing analysis time and increasing personal security. PE-Designer and PE-Analyzer are freely available at http://www.rgenome.net/pe-designer/ and http://www.rgenome.net/pe-analyzer/ without a login process.

Efficient Human Cell Coexpression System and Its Application to the Production of Multiple Coronavirus Antigens

Coproduction of multiple proteins at high levels in a single human cell line would be extremely useful for basic research and medical applications. Here, a novel strategy for the stable expression of multiple proteins by integrating the genes into defined transcriptional hotspots in the human genome is presented. As a proof-of-concept, it is shown that EYFP is expressed at similar levels from hotspots and that the EYFP expression increases proportionally with the copy number. It is confirmed that three different fluorescent proteins, encoded by genes integrated at different loci, can be coexpressed at high levels. Further, a stable cell line is generated, producing antigens from different human coronaviruses: MERS-CoV and HCoV-OC43. Antibodies raised against these antigens, which contain human N-glycosylation, show neutralizing activities against both viruses, suggesting that the coexpression system provides a quick and predictable way to produce multiple coronavirus antigens, such as the recent 2019 novel human coronavirus.

Current Status and Challenges of DNA Base Editing Tools

CRISPR-mediated DNA base editors, which include cytosine base editors (CBEs) and adenine base editors (ABEs), are promising tools that can induce point mutations at desired sites in a targeted manner to correct or disrupt gene expression. Their high editing efficiency, coupled with their ability to generate a targeted mutation without generating a DNA double-strand break (DSB) or requiring a donor DNA template, suggests that DNA base editors will be useful for treating genetic diseases, among other applications. However, this hope has recently been challenged by the discovery of DNA base editor shortcomings, including off-target DNA editing, the generation of bystander mutations, and promiscuous deamination effects in both DNA and RNA, which arise from the main DNA base editor constituents, a Cas nuclease variant and a deaminase. In this review, we summarize information about the DNA base editors that have been developed to date, introduce their associated potential challenges, and describe current efforts to minimize or mitigate those issues of DNA base editors.

Purification of an Intact Human Protein Overexpressed from Its Endogenous Locus via Direct Genome Engineering

The overproduction and purification of human proteins is a requisite of both basic and medical research. Although many recombinant human proteins have been purified, current protein production methods have several limitations; recombinant proteins are frequently truncated, fail to fold properly, and/or lack appropriate post-translational modifications. In addition, such methods require subcloning of the target gene into relevant plasmids, which can be difficult for long proteins with repeated domains. Here we devised a novel method for target protein production by introduction of a strong promoter for overexpression and an epitope tag for purification in front of the endogenous human gene, in a sense performing molecular cloning directly in the human genome, which does not require cloning of the target gene. As a proof of concept, we successfully purified intact human Reelin protein, which is lengthy (3460 amino acids) and contains repeating domains, and confirmed that it was biologically functional.

Adenine base editors catalyze cytosine conversions in human cells

Adenine base editors comprise an adenosine deaminase, evolved in vitro, and a Cas9 nickase. Here, we show that in addition to converting adenine to guanine, adenine base editors also convert cytosine to guanine or thymine in a narrow editing window (positions 5-7) and in a confined TC*N sequence context. Adenine base editor-induced cytosine substitutions occur independently of adenosine conversions with an efficiency of up to 11.2% and reduce the number of suitable targeting sites for high-specificity base editing.

Mussel-Inspired Self-Healing Metallopolymers for Silicon Nanoparticle Anodes

Polymers with supramolecular functionality are receiving increasing attention for rechargeable battery binders as strong supramolecular interactions can facilitate self-healing effects via bond recovery of the cleaved cross-links. Such self-healing capability is useful for emerging high-capacity battery materials that undergo large volume changes. Benchmarking mussel's sticky byssus cuticle, herein we report a copolymer binder with Fe³⁺-(tris)catechol coordination cross-links, which can induce a self-healing effect for silicon anodes. The high strength of the Fe³⁺-(tris)catechol coordination bond can lead to recovery of the dissociated bond that occurs from the large volume expansion of silicon. The given copolymer also contains monomer units with sufficient flexibility to increase the interchain motions for efficient Fe³⁺-(tris)catechol bond recovery. The superior electrochemical performance of the Si electrodes based on the proposed copolymer binder indicates that metallopolymers which utilize metal-organic ligand coordination for interchain cross-linking are promising binders with self-healing effects for sustainable cycling of high capacity battery electrodes.

Construction of non-canonical PAM-targeting adenosine base editors by restriction enzyme-free DNA cloning using CRISPR-Cas9

Molecular cloning is an essential technique in molecular biology and biochemistry, but it is frequently laborious when adequate restriction enzyme recognition sites are absent. Cas9 endonucleases can induce site-specific DNA double-strand breaks at sites homologous to their guide RNAs, rendering an alternative to restriction enzymes. Here, by combining DNA cleavage via a Cas9 endonuclease and DNA ligation via Gibson assembly, we demonstrate a precise and practical DNA cloning method for replacing part of a backbone plasmid. We first replaced a resistance marker gene as a proof of concept and next generated DNA plasmids that encode engineered Cas9 variants (VQR, VRER and SpCas9-NG), which target non-canonical NGA, NGCG and NG protospacer-adjacent motif (PAM) sequences, fused with adenosine deaminases for adenine base editing (named VQR-ABE, VRER-ABE and NG-ABE, respectively). Ultimately, we confirmed that the re-constructed plasmids can successfully convert adenosine to guanine at endogenous target sites containing the non-canonical NGA, NGCG and NG PAMs, expanding the targetable range of the adenine base editing.

Direct observation of DNA target searching and cleavage by CRISPR-Cas12a

Cas12a (also called Cpf1) is a representative type V-A CRISPR effector RNA-guided DNA endonuclease, which provides an alternative to type II CRISPR-Cas9 for genome editing. Previous studies have revealed that Cas12a has unique features distinct from Cas9, but the detailed mechanisms of target searching and DNA cleavage by Cas12a are still unclear. Here, we directly observe this entire process by using single-molecule fluorescence assays to study Cas12a from Acidaminococcus sp. (AsCas12a). We determine that AsCas12a ribonucleoproteins search for their on-target site by a one-dimensional diffusion along elongated DNA molecules and induce cleavage in the two DNA strands in a well-defined order, beginning with the non-target strand. Furthermore, the protospacer-adjacent motif (PAM) for AsCas12a makes only a limited contribution of DNA unwinding during R-loop formation and shows a negligible role in the process of DNA cleavage, in contrast to the Cas9 PAM.

A "Sticky" Mucin-Inspired DNA-Polysaccharide Binder for Silicon and Silicon-Graphite Blended Anodes in Lithium-Ion Batteries

New binder concepts have lately demonstrated improvements in the cycle life of high-capacity silicon anodes. Those binder designs adopt adhesive functional groups to enhance affinity with silicon particles and 3D network conformation to secure electrode integrity. However, homogeneous distribution of silicon particles in the presence of a substantial volumetric content of carbonaceous components (i.e., conductive agent, graphite, etc.) is still difficult to achieve while the binder maintains its desired 3D network. Inspired by mucin, the amphiphilic macromolecular lubricant, secreted on the hydrophobic surface of gastrointestine to interface aqueous serous fluid, here, a renatured DNA-alginate amphiphilic binder for silicon and silicon-graphite blended electrodes is reported. Mimicking mucin's structure comprised of a hydrophobic protein backbone and hydrophilic oligosaccharide branches, the renatured DNA-alginate binder offers amphiphilicity from both components, along with a 3D fractal network structure. The DNA-alginate binder facilitates homogeneous distribution of electrode components in the electrode as well as its enhanced adhesion onto a current collector, leading to improved cyclability in both silicon and silicon-graphite blended electrodes.

Mussel-Inspired Coating and Adhesion for Rechargeable Batteries: A Review

A significant effort is currently being invested to improve the electrochemical performance of classical lithium-ion batteries (LIBs) or to accelerate the advent of new chemistry-based post-LIBs. Regardless of the governing chemistry associated with charge storage, stable electrode-electrolyte interface and wet-adhesion among the electrode particles are universally desired for rechargeable batteries adopting liquid electrolytes. In this regard, recent studies have witnessed the usefulness of mussel-inspired polydopamine or catechol functional group in modifying the key battery components, such as active material, separator, and binder. In particular, the uniform conformal coating capability of polydopamine protects active materials from unwanted side reactions with electrolytes and increases the wettability of separators with electrolytes, both of which significantly contribute to the improvement of key battery properties. The wet-adhesion originating from catechol functional groups also largely increases the cycle lives of emerging high-capacity electrodes accompanied by huge volume expansion. This review summarizes the representative examples of mussel-inspired approaches in rechargeable batteries and offers central design principles of relevant coating and adhesion processes.

Mussel-Inspired Polydopamine Coating for Enhanced Thermal Stability and Rate Performance of Graphite Anodes in Li-Ion Batteries

Despite two decades of commercial history, it remains very difficult to simultaneously achieve both high rate capability and thermal stability in the graphite anodes of Li-ion batteries because the stable solid electrolyte interphase (SEI) layer, which is essential for thermal stability, impedes facile Li(+) ion transport at the interface. Here, we resolve this longstanding challenge using a mussel-inspired polydopamine (PD) coating via a simple immersion process. The nanometer-thick PD coating layer allows the formation of an SEI layer on the coating surface without perturbing the intrinsic properties of the SEI layer of the graphite anodes. PD-coated graphite exhibits far better performances in cycling test at 60 °C and storage test at 90 °C than bare graphite. The PD-coated graphite also displays superior rate capability during both lithiation and delithiation. As evidenced by surface free energy analysis, the enhanced performance of the PD-coated graphite can be ascribed to the Lewis basicity of the PD, which scavenges harmful hydrofluoric acid and forms an intermediate triple-body complex among a Li(+) ion, solvent molecules, and the PD's basic site. The usefulness of the proposed PD coating can be expanded to various electrodes in rechargeable batteries that suffer from poor thermal stability and interfacial kinetics.

Dynamic Cross-Linking of Polymeric Binders Based on Host-Guest Interactions for Silicon Anodes in Lithium Ion Batteries

We report supramolecular cross-linking of polymer binders via dynamic host-guest interactions between hyperbranched β-cyclodextrin polymer and a dendritic gallic acid cross-linker incorporating six adamantane units for high-capacity silicon anodes. Calorimetric analysis in the solution phase indicates that the given host-guest complexation is a highly spontaneous and enthalpically driven process. These findings are further verified by carrying out gelation experiments in both aqueous and organic media. The dynamic cross-linking process enables intimate silicon-binder interaction, structural stability of electrode film, and controlled electrode-electrolyte interface, yielding enhanced cycling performance. Control experiments using both α, γ-CDp with different cavity sizes and a guest molecule incorporating a single adamantane unit verified that the enhanced cycle life originates from the host-guest interaction between β-cyclodextrin and adamantane. The impact of the dynamic cross-linking is maximized at an optimal stoichiometry between the two components. Importantly, the present investigation proves that the molecular-level tuning of the host-guest interactions can be translated directly to the cycling performance of silicon anodes.

Systematic molecular-level design of binders incorporating Meldrum's acid for silicon anodes in lithium rechargeable batteries

Covalent or Noncovalent? Systematic investigation of polymeric binders incorporating Meldrum's acid reveals most critical binder properties for silicon -anodes in lithium ion batteries, that is self-healing effect facilitated by a series of noncovalent interactions.

Hyperbranched β-cyclodextrin polymer as an effective multidimensional binder for silicon anodes in lithium rechargeable batteries

Polymeric binders play an important role in electrochemical performance of high-capacity silicon (Si) anodes that usually suffer from severe capacity fading due to unparalleled volume change of Si during cycling. In an effort to find efficient polymeric binders that could mitigate such capacity fading, herein, we introduce polymerized β-cyclodextrin (β-CDp) binder for Si nanoparticle anodes. Unlike one-dimensional binders, hyperbranched network structure of β-CDp presents multidimensional hydrogen-bonding interactions with Si particles and therefore offers robust contacts between both components. Even the Si nanoparticles that lost the original contacts with the binder during cycling recover within the multidimensional binder network, thus creating a self-healing effect. Utilizing these advantageous features, β-CDp-based Si electrode shows markedly improved cycling performance compared to those of other well-known binder cases, especially when combined with linear polymers at an appropriate ratio to form hybrid binders.

Mussel-inspired adhesive binders for high-performance silicon nanoparticle anodes in lithium-ion batteries

Conjugation of mussel-inspired catechol groups to various polymer backbones results in materials suitable as silicon anode binders. The unique wetness-resistant adhesion provided by the catechol groups allows the silicon nanoparticle electrodes to maintain their structure throughout the repeated volume expansion and shrinkage during lithiation cycling, thus facilitating substantially improved specific capacities and cycle lives of lithium-ion batteries.

Electrical properties and surface morphology of SiO(x)-Pt nano-composite thin films

Recently, ceramic metals (cermets) have been widely investigated for use as embedded resistor materials. In this study, SiO-Pt nano-composite cermets were developed to control the resitivity and temperature coefficients of resistance (TCR) of embedded thin film resistors. The SiO-Pt nano-composite was prepared by the co-sputtering of a SiO(x) target and Pt chips onto glass. The experiments were conducted Pt concentrations in order to find the optimum conditions to achieve a high resistivity and low TCR. The electrical properties of the sputtered SiO-Pt thin films were investigated by probe station and their crystal structures were observed by X-Ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The surface morphology was observed by field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). It was found that the Pt particles with a size of 3 approximately 5 nm were uniformly dispersed in the SiO matrix. A stable resistivity value of 26000 approximately 57000 microomega x cm and TCR value of -197 approximately -322 ppm/K were obtained at 3.5 approximately 3.7 at.% Pt.

Toluene-induced accumulation of trehalose by Pseudomonas sp. BCNU 106 through the expression of otsA and otsB homologues

AIM

The objective of this study was to investigate toluene-induced accumulation mechanism of trehalose in a toluene-tolerant bacterium Pseudomonas sp. BCNU 106.

METHODS AND RESULTS

The accumulation of trehalose by a toluene-tolerant bacterium Pseudomonas sp. BCNU 106 was examined at various cultivation time by measuring the total intracellular trehalose content, trehalase activity and mRNA levels of the trehalose-biosynthetic genes. The pattern of trehalose accumulation corresponded to the mRNA expression pattern of the trehalose-biosynthetic genes with the maximum level at 12 h or 4 h of cultivation with 10% (v/v) toluene, respectively. The trehalose-biosynthetic genes were also cloned and sequenced. Furthermore, the effects of toluene addition on the intracellular osmotic pressure and pH were investigated. It was shown that homeostasis was maintained in the bacterial cells.

CONCLUSIONS

In a toluene-tolerant bacterium Pseudomonas sp. BCNU 106, a significant amount of trehalose was accumulated through the toluene-induced expression of the trehalose-biosynthetic genes after the exposure to toluene.

SIGNIFICANCE AND IMPACT OF THE STUDY

The accumulation of the high level of intracellular trehalose was preceded by the expression of otsA/B genes in toluene-tolerant bacteria, contributing to the elucidation of the tolerance mechanism.

Covered retrievable tracheobronchial hinged stent: an experimental study in dogs

PURPOSE

To evaluate the safety and technical feasibility of the use of a covered retrievable tracheobronchial hinged stent and investigate the histopathologic airway changes after placement and removal of the stent in dogs.

MATERIALS AND METHODS

The experimental stent was composed of tracheal and bronchial stents that were connected together at their ends. Each stent was woven from a single thread of 0.2-mm-diameter nitinol wire filament in a tubular configuration and covered with polyurethane solution by a dipping method. Drawstrings were attached at the upper end of the tracheal stent for stent removal. Under fluoroscopic guidance, 20 stents were placed at the lower trachea and left main bronchus in 20 dogs and were electively removed 4 weeks (n = 10) or 8 weeks (n = 10) after placement. Ten dogs were killed just after stent removal and the remaining 10 were killed 2 weeks after stent removal.

RESULT

Stents were successfully placed in all dogs. Pneumonia was observed in three dogs. Stent migration occurred in seven dogs (35%). Except for two cases of stent expectoration, 18 stents were easily removed within a few minutes. There was considerable granulation tissue proliferation and inflammatory reaction in the airways of the dogs that were killed just after stent removal. The pathologic changes of the airways returned to almost-normal conditions 2 weeks after stent removal.

CONCLUSION

Placement and removal of a covered retrievable tracheobronchial hinged stent seems to be feasible, and histopathologic changes of the airway related to the stents returned to normal 2 weeks after stent removal.

Solitary fibrous tumor in the buccal space: MR findings with pathologic correlation

We report MR findings in a case of a solitary fibrous tumor involving the buccal space in a middle-aged man. On MR images, most of the mass was isointense and hyperintense to the muscle on T1- and T2-weighted images, respectively, and showed homogeneously strong enhancement on contrast-enhanced T1-weighted images. The medial peripheral portion, which was isointense on T2-weighted images and showed less enhancement on contrast-enhanced T1-weighted images, corresponded to the hypocellular and collagenous sclerotic area on pathologic correlation.

A new method for conservation of nitrogen in aerobic composting processes

Several factors, such as pH, C/N ratio, temperature, mixing and turning, and aeration rate, could affect the loss of ammonia in composting reactions. Substantial loss of ammonia can reduce the nutrient value of the compost product and may lead to a severe odor problem in the composting facility. A new method for conservation of ammonia in composting was proposed and tested in this study. The ammonia being produced during the composting was precipitated into struvite crystals by addition of Mg and P salts. Ammonia volatilization was greatly reduced by this method and it also contributed to a remarkable increase in total ammoniacal-N (TAN) content in the compost, reaching up to 1.4% of dry mass. This value of TAN content was 3-5 times higher than that in normal compost. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses confirmed the formation of struvite crystals in the aerobic composting process.

Two-phase helical CT for detection of early gastric carcinoma: importance of the mucosal phase for analysis of the abnormal mucosal layer

PURPOSE

To evaluate the efficacy of two-phase dynamic helical computed tomography (CT), including the gastric mucosal phase, for detection of early gastric carcinoma with typical hyperattenuating and atypical nonhyperattenuating enhancement patterns.

METHOD

Two-phase helical CT scanning was performed using the water-filling method as negative oral contrast material for 212 patients with proven adenocarcinoma on endoscopic biopsy. Two gastrointestinal radiologists prospectively analyzed the focal alterations of the inner hyperattenuating mucosal layer and the outer hypoattenuating layer before the information obtained at barium study and pathologic examination was available. The first, so-called mucosal phase was obtained at 38-45 seconds after the start of intravenous injection of contrast material for a total of 150 ml/sec at a rate of 4 ml/sec to obtain maximum enhancement of the inner mucosal layer. The second delayed phase was obtained at 3 minutes.

RESULTS

Fifty-four cases of early gastric cancer were suspected on two-phase helical CT preoperatively. Postoperatively, 49 cases of early gastric cancer were pathologically confirmed. The detection rate for the typical hyperattenuating early gastric cancer, that is the type I enhancement pattern defined as the localized thickening of the inner hyperattenuating layer, using two-phase helical CT was 18% (9/49 patients). The type 2 enhancement pattern, defined as the focal interruption of the inner hyperattenuating mucosal layer without abnormal enhancement of the outer hypoattenuating layer on the mucosal phase, was seen in 15 cases. These were pathologically confirmed as early gastric cancer IIb + IIc (three patients), IIc (four patients), IIc + IIa (one patient), IIc + III (three patients), IIb + IIc (one patient), and advanced cancer (T2) lesions (three patients). The type 3 enhancement pattern was defined as the focal polypoid protrusion of the inner hyperattenuating layer without abnormal enhancement of the outer thickened hypoattenuating layer on the mucosal phase, and was seen in seven patients who were pathologically confirmed with early gastric cancer IIb + IIc (three patients), IIc + IIa (one patient), and IIc + lIb (three patients). The lesions became less distinct on the delayed phase. Five T2 advanced gastric cancers were falsely interpreted as early gastric cancer. The detection rate for early gastric cancer after considering type 2 and 3 atypical enhancement patterns was increased to 57% (28/49 patients).

CONCLUSION

Helical CT with two-phase scan including the mucosal phase was efficient for identifying the enhancement patterns of early gastric cancer.

Adult T cell leukemia/lymphoma with lymphopenia in a Korean

We experienced a case of adult T cell leukemia/lymphoma (ATLL) in a 48-year-old Korean female, who has never been abroad since birth and no history of blood transfusion. The patient had hypercalcemia and multiple lymphadenopathy. Histopathologic study of left cervical lymph node (LN) and bone marrow (BM) revealed that infiltrates of malignant lymphoid cells were composed of small, medium and large cells with pleomorphic nuclei. Smears of peripheral blood (PB) showed lymphopenia (16%) with the appearance of a few atypical lymphoid cells (less than 2%), but not the typical clover leaf cells seen in ATLL. Immunophenotypic study of LN and BM revealed T cell phenotype. PB showed increased CD4+ T cell (T(H), CD3/CD4+, 57%) and decreased CD8+ T cell counts (T(S), CD3/CD8+, 6.7%). The sera of the patient and her family were reactive for HTLV-I antibody. The specific sequences of pol, env, and tax of HTLV-I DNA were detected in the lymphoma cells and peripheral blood mononuclear cells (PBMC) using polymerase chain reaction. Ultrastructural examination of PBMC confirmed numerous type c virus particles in extracellular space. This case was an acute type of ATLL without overt leukemic features in PB. Despite chemotherapy and intensive conservative treatment, she died 3 months after admission.

Fast T2-weighted liver MR imaging: comparison among breath-hold turbo-spin-echo, HASTE, and inversion recovery (IR) HASTE sequences

BACKGROUND

To evaluate the diagnostic efficacy of fast T2-weighted magnetic resonance (MR) imaging sequences on image quality, hepatic lesion detection, and lesion conspicuity.

METHODS

Three breath-hold, fast T2-weighted sequences with turbo-spin-echo (TSE), half-Fourier acquisition single-shot TSE (HASTE), and inversion recovery (IR) HASTE techniques were examined for 43 lesions in 20 consecutive patients. Evaluation was performed qualitatively on image quality and lesion detectability and quantitatively on lesion conspicuity by using lesion/liver signal-intensity and contrast-to-noise ratios.

RESULTS

Artifacts were significantly less present on the HASTE sequence (p < 0.01). Both TSE and HASTE sequences detected 39 lesions (91% each); the IR HASTE sequence detected 37 (86%). IR HASTE sequence showed a significantly higher signal-intensity ratio than did the others (p < 0.01).

CONCLUSIONS

Breath-hold TSE versus breath-hold HASTE or IR HASTE is still the most robust sequence in lesion detection, image quality, and lesion conspicuity. However, the HASTE sequence offers good lesion detection and image quality, and the IR HASTE has a better signal-intensity ratio.

MR cholangiopancreatography of pancreaticobiliary diseases: comparing single-shot RARE and multislice HASTE sequences

OBJECTIVE

In this study, we compared the single-shot rapid acquisition with relaxation enhancement (RARE) sequence with the multislice half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence to assess the ability of each technique to show various pancreaticobiliary diseases using MR cholangiopancreatography.

SUBJECTS AND METHODS

MR cholangiopancreatography was performed using both the single-shot RARE and the multislice HASTE pulse sequences in 80 consecutive subjects in whom we had proof of a range of diagnoses. The study population included healthy subjects (n = 9), patients with benign lesions (n = 41), and patients with malignant lesions (n = 30). We analyzed each image using the following criteria: the cause of the lesions, the image quality (i.e., the amount of artifact and the sharpness of anatomic structures such as the right and left hepatic ducts, the extrahepatic bile duct, and the main pancreatic duct), and the reviewers' preference of images. The images were evaluated independently by two radiologists who were unaware of the results of the other cholangiopancreatographic sequence and of the diagnosis.

RESULTS

Artifacts were less prominent in images that were obtained using the single-shot RARE sequence (p = .0192); however, the sharpness of anatomic structures was the same using either sequence (p = .1673). For images that were obtained using the single-shot RARE technique, the sensitivity, specificity, and accuracy in distinguishing malignant from other abnormalities were 83%, 78%, and 80%, respectively; for the multislice HASTE technique, these values were 77%, 72%, and 74%, respectively (p > .05). Disease-specific accuracy in determining the correct diagnosis was 54% and 59%, respectively (p > .05). In patients in whom all the ducts needed to be defined, the single-shot RARE technique was preferred to the multislice HASTE technique (p < .01).

CONCLUSION

The single-shot RARE technique shows fewer artifacts and is preferred to the multislice HASTE technique. However, both techniques show the same degree of sharpness of anatomic structures, both are able to reveal malignant diseases, and both provide enough information to determine a specific diagnosis.

Biliary stricture caused by blunt abdominal trauma: clinical and radiologic features in five patients

PURPOSE

To evaluate the clinical and radiologic features of biliary stricture after blunt abdominal trauma and to report the results of endoscopic stent placement.

MATERIALS AND METHODS

Medical records and radiologic findings were reviewed in five patients with biliary stricture after blunt abdominal trauma. The level, length, and contour of the strictures were analyzed with endoscopic retrograde cholangiopancreatography (ERCP). Computed tomographic (CT) scans were also reviewed to determine the presence of biliary dilatation, configuration of the injured bile duct, and ancillary abdominal findings. Results from endoscopic stent placement were evaluated in all patients.

RESULTS

Stricture occurred in the suprapancreatic portion of the common bile duct in four patients and in the intrapancreatic portion in one patient. At ERCP, the stricture contour was concentric and smooth in three patients, eccentric and smooth in one, and abruptly terminated in one. CT showed abrupt narrowing of the common bile duct with dilatation of the proximal portion in all patients. Endoscopic stent placement was successful in all patients.

CONCLUSION

Patients with biliary stricture after blunt abdominal trauma exhibit a delayed onset of symptoms. A correct diagnosis may be difficult on the basis of findings from CT or ERCP alone without a clinical history or evidence of contusions at other sites.

Acute occlusion of the middle cerebral artery: early evaluation with triphasic helical CT--preliminary results

PURPOSE

To evaluate use of triphasic helical computed tomography (CT) for early diagnosis of occlusion and assessment of ischemia in cases of acute middle cerebral arterial occlusion.

MATERIALS AND METHODS

Thirty-five patients with acute ischemia underwent triphasic helical CT within 6 hours after symptom onset. Early arterial, perfusion, and delayed phase CT scans were obtained 18, 30, and 80 seconds, respectively, after contrast material administration. Eighteen patients had proximal middle cerebral arterial occlusion diagnosed at magnetic resonance (MR) or digital subtraction angiography. Follow-up CT or MR imaging was performed in all patients. Two independent observers interpreted images for signs of arterial occlusion, collateral vessels, and the ischemic zone.

RESULTS

One observer found at least one of three signs in 17 of the 18 patients with occlusion, and the other found at least one sign in all 18: Early decreased arterial contrast enhancement was seen by both observers in 11 patients (kappa = 0.77), a nonenhancing arterial segment was seen by the two observers in 12 and 14 (kappa = 0.73), and delayed asymmetric arterial enhancement was seen in 13 and 16 (kappa = 0.49). Triphasic CT findings of the ischemic zone were consistent with follow-up CT or MR imaging findings in seven of 12 patients.

CONCLUSION

Triphasic helical CT is useful for early diagnosis of acute proximal middle cerebral arterial occlusion and assessment of the ischemic zone.

Application of MRI for small intestinal diseases

Until recently, MRI has not been considered to be suitable for the evaluation of the small intestine due to artifacts associated with bowel peristalsis or respiration. However, recent advances of MR techniques enable the acquisition of clear images of the small intestine. Therefore, the purpose of this article is to review the details for the application of MRI in patients with small intestinal diseases. This article discusses bowel preparation and oral contrast agents as well as MR techniques and pulse sequences. Thereafter, the usefulness of MRI for the lesions in the peritoneal cavity or in the gastrointestinal tract are discussed. Small intestinal lesions are categorized into inflammatory, neoplastic, ischemic, and obstructive bowel diseases. In conclusion, MRI can be used as an alternate modality of choice for imaging various diseases of the small intestine.

Vasculature in hepatocellular carcinoma after transcatheter arterial chemoembolization: comparison of power and color Doppler sonography

The purpose of this study was to compare power Doppler sonography with conventional color Doppler sonography for the detection of the vascularity of hepatocellular carcinomas after transcatheter arterial chemoembolization. Of the 93 embolized hepatocellular carcinomas, hypervascularity was demonstrated in 36 on angiography; power Doppler sonography correctly identified pulsatile flow signals in 33 (92%) of these 36, whereas color Doppler sonography identified flow signals in 24 (67%). A statistically significant difference was noted when the sizes of the nodules were 30 mm or less. Despite technical difficulties, such as flash artifact, power Doppler sonography is superior to color Doppler sonography for detection of hypervascularity, especially in small embolized nodules of hepatocellular carcinoma (30 mm or less in diameter).

Differentiation of simple and strangulated small-bowel obstructions: usefulness of known CT criteria

PURPOSE

To evaluate the usefulness of known computed tomographic (CT) criteria for the differentiation of simple and strangulated small-bowel obstructions.

MATERIALS AND METHODS

CT scans of 84 patients with simple (n = 43) and strangulated (n = 41) small-bowel obstructions caused by adhesions, hernia, and volvulus were reviewed retrospectively. Diagnoses were made with surgery (n = 55) and during clinical follow-up (n = 29). CT criteria evaluated were configuration of obstructed bowel loop, target sign, bowel wall thickening and enhancement, changes in mesentery and mesenteric vasculature, and amount and attenuation of ascites.

RESULTS

CT findings that enabled the detection of strangulated obstructions were poor or no enhancement of bowel wall (sensitivity, 34%; specificity, 100%) and a serrated beak (sensitivity, 32%; specificity, 100%). When these two findings were excluded from analysis, a large amount of ascites, an unusual course of mesenteric vasculature, and diffuse engorgement of mesenteric vasculature were shown to be useful CT findings for performing multivariate regression analysis. Application of these five CT findings enabled identification of 35 (85%) of 41 patients with strangulated obstructions.

CONCLUSION

Detecting a combination of selected, known CT criteria increases the diagnostic accuracy of CT to enable differentiation of simple and strangulated small-bowel obstructions.

ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb

OBJECTIVE

The purpose of this study was to evaluate ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb.

CONCLUSION

Although rare, the diagnosis of ectopic drainage of the common bile duct into the duodenal bulb is important to prevent inadvertent damage during biliary tract or gastric surgery and to clarify the cause of chronic peptic ulcers.

Gastrointestinal involvement in Henoch-Schönlein syndrome: CT findings

OBJECTIVE

The purpose of this study was to describe the CT features of gastrointestinal involvement in seven patients with Henoch-Schönlein syndrome.

CONCLUSION

Although the incidence of Henoch-Schönlein syndrome is low, it should be considered when CT scans show multifocal areas of bowel-wall thickening, mesenteric edema, vascular engorgement, and nonspecific lymphadenopathy. It should be considered especially in young patients with acute gastrointestinal symptoms.

Usefulness of CT in patients with ischemic colitis proximal to colonic cancer

OBJECTIVE

The purpose of this study was to assess the usefulness of CT scans for distinguishing ischemic from tumoral segments in patients with colonic carcinoma complicated by proximal bowel ischemia.

MATERIALS AND METHODS

CT scans of 20 patients with ischemic colitis proximal to obstructing colonic carcinoma were reviewed retrospectively. The concomitant presence of ischemia was proven on pathologic examinations in 12 patients and on barium enema studies in the remaining eight patients. CT scans were analyzed for the involved site and length, bowel wall thickness, enhancing pattern of both tumoral and ischemic segments, and changes in the pericolic space. The results of tumor staging on CT scans were compared with those of pathologic findings.

RESULTS

Distinction of ischemic from tumoral segments could be made on CT in 15 (75%) of the 20 patients. Of the 20 patients, 18 had ischemic segments contiguously proximal to the tumoral segment, and the remaining two patients had a skipped zone with intervening normal mucosa. Tumoral segments were irregularly thickened in most patients. Maximum thickness ranged from 0.8 to 4.5 cm (mean, 2.0 cm). Most often the ischemic segment was concentrically and smoothly thickened, ranging from 0.6 to 1.5 cm (mean, 1.0 cm). The tumoral segments enhanced heterogeneously in 12 patients and enhanced homogeneously in the remaining eight, whereas ischemic segments enhanced homogeneously in 14 (70%) patients and heterogeneously in six. On CT scans, we saw the target or double halo sign in four (20%) patients. Pericolic vascular engorgement was 19 patients, two of whom were overstaged because pericolic vascular engorgement was interpreted as tumor infiltration.

CONCLUSION

Although CT findings are not specific for certain groups of patients, they are often helpful in distinguishing tumoral from ischemic segments in patients with ischemic colitis proximal to colonic carcinoma. An understanding of this pathologic entity may increase the accuracy of CT for staging colonic carcinoma.

Thin-section CT findings of the lungs: experimentally induced bronchial and pulmonary artery obstruction in pigs

OBJECTIVE

The purpose of this study was to investigate whether a mosaic pattern of lung attenuation, or lobular low attenuation, is revealed on CT imaging after induction of bronchial and pulmonary artery obstruction in pigs.

MATERIALS AND METHODS

Eight anesthetized and ventilated pigs, four for bronchial obstruction and four for pulmonary artery obstruction, were examined with thin-section CT. Bronchial obstruction was induced at the subsegmental level using 2- to 3-mm radiopaque silicon spheres at 14 sites. Pulmonary artery obstruction was induced at 11 sites by dislodging 2- to 3-mm silicon spheres at the level of the superior vena cava. CT scans were obtained at end expiration immediately after the obstruction in all pigs (n = 8) and after 1 day (n = 3), 3 days (n = 5), 7 days (n = 4), 14 days (n = 4), and 28 days (n = 3).

RESULTS

Of the 14 sites of bronchial obstruction, six sites (43%) on the immediate scans showed a lobular distribution of low attenuation distal to the spheres, which changed to atelectasis, consolidation, or normal on follow-up CT. Of the four sites that did not show changes in lung attenuation on immediate CT scans, two sites showed lobular low attenuation after 1 day. The mean attenuation value +/- SD for the lobular low attenuation was -737 H +/- 122 and that of the adjacent lung was -522 H +/- 53 (p = .0077). None of the pulmonary artery obstruction sites showed visible change in lung attenuation, and mean attenuation values for obstructed sites and unobstructed sites did not show significant differences when scanned as many as 28 days after the immediate scans.

CONCLUSION

Lobular low attenuation on thin-section CT was induced by bronchial obstruction, but we found no change in lung attenuation due to obstruction of the pulmonary arteries as many as 28 days after the immediate scans.

Doppler sonographic resistive index in obstructed kidneys

Doppler sonographic findings were correlated with symptoms and intravenous urographic findings in 31 patients with unilateral renal obstruction and in 30 control subjects. No significant correlation was found between resistive index and symptom duration or between resistive index and pelvicalyceal opacification time on intravenous urography. With a cutoff resistive index of 0.7, the sensitivity was 19.3% in diagnosing unilateral obstruction; however, it was 80% in the subgroup with acute symptoms and severely delayed pelvicalyceal opacification time. Doppler sonography has very low sensitivity in diagnosing unilateral renal obstruction, but it may be useful when the obstruction is acute and severe.

Activation of Ca(2+)-activated K+ channels by beta agonist in rabbit coronary smooth muscle cells

Isoproterenol (ISO), a beta agonist, causes hyperpolarization of coronary smooth muscle cells via an increase in K+ conductance. This hyperpolarization may cause the coronary vasorelaxation by decreasing the cytoplasmic Ca2+ concentration. It is well known that the activation of beta adrenoreceptors stimulates the adenylate cyclase activity, and the resulting K+ channel phosphorylation by cAMP-dependent protein kinase may be responsible for ISO-induced increase in K+ channel activity. However, it is not clear whether the increase in K+ channel activity by ISO is exclusively due to the activation of adenylate cyclase or not. In this research, the effect of ISO on the isometric tension and the mechanism of ISO-induced K+ channel activation were investigated in various patch clamp conditions. The summarized results are as follows. ISO- and pinacidil induced vasorelaxation was significantly inhibited by the application of TEA or by increasing the external K+ concentration. In the whole cell clamp mode, application of ISO increased K+ outward current, and this effect was completely eliminated by propranolol. In the cell-attached patch, application of ISO or forskolin increased Ca(2+)-activated K+ channel activity. Application of ISO to the bath in the outside-out patches or GTP in the inside-out patches stimulated Ca(2+)-activated K+ channels. From the above results, both A-kinase dependent channel phosphorylation and direct GTP-binding protein mediated effect might be responsible for the the activation of Ca(2+)-activated K+ channel by ISO in rabbit coronary smooth muscle cells. And this K+ channel activation also contributes to the ISO-induced vasorelaxation.

Hemolytic uremic syndrome: MR findings of CNS complications

MR findings of a patient with hemolytic uremic syndrome involving the CNS are described. Abnormal high signal intensity on T2-weighted images combined with swelling in the lentiform nucleus, posterior limb of internal capsule, external capsule bilaterally, and left extreme capsule was shown on initial MR; a small low signal intensity in the left putamen on T1- and T2-weighted images and generalized atrophy in the area of high signal intensity on previous T2-weighted images was shown on follow-up MR. These findings indicate infarct with focal hemorrhage, which is one of the histopathological features of CNS complication in hemolytic uremic syndrome.

Interaction with phospholipids of a membrane thiol peptidase that is essential for the signal transduction of mating pheromone in Rhodosporidium toruloides

Interaction with phospholipids of a membrane thiol peptidase [referred to as trigger peptidase (TPase), T. Miyakawa et al. (1987) J. Bacteriol. 169, 1626-1631] that plays a key role in the signalling of a lipopeptidyl mating pheromone at the cell surface of pheromone-target cell (mating type a) of Rhodosporidium toruloides was studied. The activity of highly purified TPase which requires phospholipids was restored by reconstitution of the enzyme into liposomes prepared with phospholipids extracted from the yeast cell. The presence of Ca2+ was essential for both the reconstitution process and the catalytic reaction of TPase. Triton X-100 mixed micelles containing phospholipids also activated the enzyme. The specificity and stoichiometry of activation by phospholipids was investigated by determination of TPase in the presence of mixed micelles that contained defined classes and numbers of phospholipid molecules in the Triton X-100 micelles. It was demonstrated that TPase is activated by mixed micelles containing 2-6 molecules of phosphatidylserine or phosphatidylethanolamine. Other phospholipids of the membranes of this organism, such as phosphatidylcholine and phosphatidylglycerol, had little effect on activation, indicating that the amino group of the phospholipids may be required for the function of TPase. Direct evidence for the interaction of TPase and Triton X-100/phosphatidylserine mixed micelles was obtained by molecular sieve chromatography on Sephacryl S-200. These data established that a phospholipid bilayer is not a requirement for TPase activation, and that the purified enzyme can be activated by a relatively small number of phospholipid molecules of specific classes.

Purification and characterization of a Ca2+-dependent membrane peptidase involved in the signaling of mating pheromone in Rhodosporidium toruloides

A mating-type-specific, membrane thiol peptidase (referred to as trigger peptidase) that seems to play a key role in the transmembrane signaling of the lipopeptidyl mating pheromone rhodotorucine A at the cell surface of mating type a cells of Rhodosporidium toruloides (T. Miyakawa, M. Kaji, T. Yasutake, Y.K. Jeong, E. Tsuchiya, and S. Fukui, J. Bacteriol. 162:294-299, 1985) was purified to homogeneity and characterized. The following lines of evidence support the contention that the enzyme we purified was the trigger peptidase: the identical specificity of hydrolysis at the Arg-Asn sequence of rhodotorucine A and the sensitivity of the reaction to sulfhydryl-blocking reagents; the identical specificity for the substrate, with a strict requirement for the presence of the lipid moiety; and the absence of the corresponding activity in the pheromone-producing strain (mating type A) and in a sterile mutant strain, M-39 (type a), that lacks trigger peptidase activity in vivo. The apparent molecular weight of trigger peptidase was estimated to be 68,000 by Sepharose 6B gel filtration in the presence of octylglucoside and 63,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Trigger peptidase alone was inactive but exhibited enzymatic activity with the simultaneous addition of Ca2+, membrane phospholipids, and a nonionic detergent such as octylglucoside. The concentration of Ca2+ required for maximum activation was approximately 1 mM. Only Mn2+ could replace Ca2+ at comparable concentrations. Among the phospholipids tested, only phosphatidylserine and phosphatidylethanolamine supported trigger peptidase activation. Solubilized trigger peptidase was strongly inhibited by antipain and phosphoramidon.

Inhibition of membrane Ca2+-ATPase in vitro by mating pheromone in Rhodosporidium toruloides, a heterobasidiomycetous yeast

Direct addition of physiological concentrations of rhodotorucine A, a lipopeptide mating pheromone of Rhodosporidium toruloides, to the particulate fraction of the target cell strongly inhibited Ca2+-ATPase activity. The pheromone effect was mating-type specific. Membrane Ca2+-ATPase solubilized by a nonionic detergent and further purified by calmodulin-affinity chromatography was also inhibited by the pheromone. Rhodotorucine A S-oxide, a biologically inactive analogue, had no effect on Ca2+-ATPase. The results suggested that the inhibition of membrane Ca2+-ATPase is a critical event in the signaling of mating pheromone and the inhibition of membrane Ca2+-pump could be responsible for the pheromone-induced rapid raise of intracellular Ca2+ concentration reported.

Transient increase of Ca2+ uptake as a signal for mating pheromone-induced differentiation in the heterobasidiomycetous yeast Rhodosporidium toruloides

The role of Ca2+ for the signaling of rhodotorucine A, a mating pheromone of Rhodosporidium toruloides, was investigated. The efficiency with which the target cells responded to the mating pheromone was dependent on the Ca2+ concentration in the medium. The pheromone induced a very rapid and transient increase of Ca2+ uptake in the recipient cell. We concluded that the transient increase in the intracellular Ca2+ concentration could play an essential role in the control of differentiation by the pheromone.

Involvement of protein sulfhydryls in the trigger reaction of rhodotorucine A, a farnesyl peptide mating pheromone of Rhodosporidium toruloides

The involvement of protein sulfhydryls for the signaling of rhodotorucine A, a mating pheromone produced by mating type A cells of Rhodosporidium toruloides, was investigated by the use of sulfhydryl compounds. The sulfhydryl-blocking reagent 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB; Ellman's reagent) strongly inhibited both the biological effect of the pheromone on the recipient cell and the hydrolysis of the pheromone, which is catalyzed by the mating type-specific surface endopeptidase of the recipient cell. Conversely, the two reactions were markedly enhanced by the presence of the reducing reagent dithiothreitol. The inhibitory effect of DTNB on the pheromone response of the recipient cell was specific to an initial stage of the differentiation; once it had initiated, the reagent had no effect on its progression. The results suggested that dithiothreitol enhances and DTNB impairs the efficiency with which the pheromone triggers sexual d differentiation. The reaction of DTNB with cellular protein sulfhydryls was highly restricted to those at the exterior surface of the membrane due to the impermeability of the reagent through the membrane. Phosphorylation of endogenous proteins, which is modulated by the pheromone added to an in vitro phosphorylation system, was also blocked by DTNB. The results showed that sulfhydryl groups are involved in the pheromone hydrolysis by the surface endopeptidase of the recipient cell and that pheromone metabolism is indispensable for the signaling reaction. We suggest that the modulation of protein phosphorylation of membrane proteins by the pheromone is an initial transmembrane response coupled to pheromone metabolism.