Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Metformin suppresses progression of muscle aging via activation of the AMP kinase-mediated pathways in Drosophila adults

OBJECTIVE

Metformin, a medicine used for the treatment of type 2 diabetes, was previously reported to suppress age-dependent hyperproliferation of intestinal stem cells in Drosophila. Here, we aimed to investigate its anti-aging effects on other tissues, such as adult muscle and elucidate the mechanisms underlying the anti-ageing effect.

MATERIALS AND METHODS

To evaluate the anti-muscle ageing effect of Metformin, we visualized ubiquitinated protein aggregates accumulated in adult muscle as the flies age by immunostaining and measured the total pixel size of the aggregates. We altered gene expression in the muscle by induction of dsRNA against the relevant mRNAs or mRNAs encoding the constitutively active mutant proteins using the Gal4/UAS system. We determined the mRNA levels by quantitative Real Time-Polymerase Chain Reaction (QRT-PCR).

RESULTS

Continuous metformin feeding significantly extended the lifespan of Drosophila adults. Furthermore, the feeding suppressed the aging-dependent accumulation of ubiquitinated aggregates in adult muscle. To delineate the mechanism through which metformin influences the muscle aging phenotype, we induced the constitutively active AMPK specifically in the muscles and found that the activation of the AMPK-mediated pathway was sufficient for the anti-aging effect of Metformin. Furthermore, the AMPK-mediated downregulation of Tor-mediated pathways, subsequent induction of an eIF-4E inhibitor were involved in the effect. These genetic data suggested that the metformin effect is related to the partial suppression of protein synthesis in ribosomes. Furthermore, metformin stimulated autophagy induction in adult muscles.

CONCLUSIONS

Our results suggest that metformin can be regarded as an anti-aging compound in Drosophila muscle. The stimulation of autophagy was also involved in the anti-aging effect, which delayed the progression of muscle aging in Drosophila adults.

Quantifying the Size and Duration of a Microburst-Producing Chorus Region on 5 December 2017

Microbursts are impulsive (<1 s) injections of electrons into the atmosphere, thought to be caused by nonlinear scattering by chorus waves. Although attempts have been made to quantify their contribution to outer belt electron loss, the uncertainty in the overall size and duration of the microburst region is typically large, so that their contribution to outer belt loss is uncertain. We combine datasets that measure chorus waves (Van Allen Probes [RBSP], Arase, ground-based VLF stations) and microburst (>30 keV) precipitation (FIREBIRD II and AC6 CubeSats, POES) to determine the size of the microburst-producing chorus source region beginning on 5 December 2017. We estimate that the long-lasting (∼30 hr) microburst-producing chorus region extends from 4 to 8Δ MLT and 2-5Δ L. We conclude that microbursts likely represent a major loss source of outer radiation belt electrons for this event.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Scent test using Caenorhabditis elegans to screen for early-stage pancreatic cancer

Although early detection and diagnosis are indispensable for improving the prognosis of patients with pancreatic cancer, both have yet to be achieved. Except for pancreatic cancer, other cancers have already been screened through scent tests using animals or microorganisms, including Caenorhabditis elegans. While such a method may greatly improve the prognosis of pancreatic cancer, no studies have investigated the same, mainly given the difficulty of collecting suitable samples from patients with early-stage pancreatic cancer. In this study, we organized a nationwide study group comprising high-volume centers throughout Japan to collect patients with very-early-stage pancreatic cancer (stage 0 or IA). We initially performed an open-label study involving 83 cases (stage 0–IV), with subsequent results showing significant differences after surgical removal in stage 0–IA (×10 dilution: p < 0.001; ×100 dilution: p < 0.001). Thereafter, a blinded study on 28 cases (11 patients with stage 0 or IA disease and 17 healthy volunteers) was conducted by comparing very-early-stage pancreatic cancer patients with healthy volunteers to determine whether C. elegans could detect the scent of cancer for the diagnosis of early-stage pancreatic cancer. Preoperative urine samples had a significantly higher chemotaxis index compared to postoperative samples in patients with pancreatic cancer [×10 dilution: p < 0.001, area under the receiver operating characteristic curve (AUC) = 0.845; ×100 dilution: p < 0.001, AUC = 0.820] and healthy volunteers (×10 dilution: p = 0.034; ×100 dilution: p = 0.088). Moreover, using the changes in preoperative and postoperative chemotaxis index, this method had a higher sensitivity for detecting early pancreatic cancer compared to existing diagnostic markers. The clinical application C. elegans for the early diagnosis of cancer can certainly be expected in the near future.

Rocuronium priming for tracheal intubation in COVID-19 patients

Priming doses of non-depolarising neuromuscular blocking drugs given before administration of anaesthetic agents have been used to hasten the onset of neuromuscular blockade. In the settings of coronavirus disease 2019 (COVID-19), this could be used to reduce the apnoeic, and potentially aerosol-generating, window. To our knowledge, we report the first cases of tracheal intubation with rocuronium for COVID-19 using the priming principle. Both patients needed their tracheas intubated for severe hypoxia using a rapid sequence induction technique with a priming dose of rocuronium. Despite adequate pre-oxygenation a sudden, unexpected fall in arterial oxygen saturations was observed in both patients after administration of a priming dose of 2 mg of rocuronium. Clinicians should consider this possible risk associated with priming doses of neuromuscular blocking drugs in the management of patients with respiratory failure due to COVID-19.

COVID-19 Drug Discovery Using Intensive Approaches

Since the infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported in China during December 2019, the coronavirus disease 2019 (COVID-19) has spread on a global scale, causing the World Health Organization (WHO) to issue a warning. While novel vaccines and drugs that target SARS-CoV-2 are under development, this review provides information on therapeutics which are under clinical trials or are proposed to antagonize SARS-CoV-2. Based on the information gained from the responses to other RNA coronaviruses, including the strains that cause severe acute respiratory syndrome (SARS)-coronaviruses and Middle East respiratory syndrome (MERS), drug repurposing might be a viable strategy. Since several antiviral therapies can inhibit viral replication cycles or relieve symptoms, mechanisms unique to RNA viruses will be important for the clinical development of antivirals against SARS-CoV-2. Given that several currently marketed drugs may be efficient therapeutic agents for severe COVID-19 cases, they may be beneficial for future viral pandemics and other infections caused by RNA viruses when standard treatments are unavailable.

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

Multiple time-scale beats in aurora: precise orchestration via magnetospheric chorus waves

The brightness of aurorae in Earth’s polar region often beats with periods ranging from sub-second to a few tens of a second. Past observations showed that the beat of the aurora is composed of a superposition of two independent periodicities that co-exist hierarchically. However, the origin of such multiple time-scale beats in aurora remains poorly understood due to a lack of measurements with sufficiently high temporal resolution. By coordinating experiments using ultrafast auroral imagers deployed in the Arctic with the newly-launched magnetospheric satellite Arase, we succeeded in identifying an excellent agreement between the beats in aurorae and intensity modulations of natural electromagnetic waves in space called “chorus”. In particular, sub-second scintillations of aurorae are precisely controlled by fine-scale chirping rhythms in chorus. The observation of this striking correlation demonstrates that resonant interaction between energetic electrons and chorus waves in magnetospheres orchestrates the complex behavior of aurora on Earth and other magnetized planets.

Platelet thrombus formation in eHUS is prevented by anti-MBL2

E. coli associated Hemolytic Uremic Syndrome (epidemic hemolytic uremic syndrome, eHUS) caused by Shiga toxin-producing bacteria is characterized by thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury that cause acute renal failure in up to 65% of affected patients. We hypothesized that the mannose-binding lectin (MBL) pathway of complement activation plays an important role in human eHUS, as we previously demonstrated that injection of Shiga Toxin-2 (Stx-2) led to fibrin deposition in mouse glomeruli that was blocked by co-injection of the anti-MBL-2 antibody 3F8. However, the markers of platelet thrombosis in affected mouse glomeruli were not delineated. To investigate the effect of 3F8 on markers of platelet thrombosis, we used kidney sections from our mouse model (MBL-2+/+ Mbl-A/C-/-; MBL2 KI mouse). Mice in the control group received PBS, while mice in a second group received Stx-2, and those in a third group received 3F8 and Stx-2. Using double immunofluorescence (IF) followed by digital image analysis, kidney sections were stained for fibrin(ogen) and CD41 (marker for platelets), von-Willebrand factor (marker for endothelial cells and platelets), and podocin (marker for podocytes). Electron microscopy (EM) was performed on ultrathin sections from mice and human with HUS. Injection of Stx-2 resulted in an increase of both fibrin and platelets in glomeruli, while administration of 3F8 with Stx-2 reduced both platelet and fibrin to control levels. EM studies confirmed that CD41-positive objects observed by IF were platelets. The increases in platelet number and fibrin levels by injection of Stx-2 are consistent with the generation of platelet-fibrin thrombi that were prevented by 3F8.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

Relationship Among Establishment Durations, Kin Relatedness, Aggressiveness, and Distance Between Populations of Eight Invasive Argentine Ant (Hymenoptera: Formicidae) Supercolonies in Japan

We investigated kin relatedness and kin-recognition abilities of the Argentine ant, Linepithema humile (Mayr), an invader from North America that has pervaded Japan for 20 yr, using genetic analyses and behavioral bioassays. From these data and interactions among factors, we formulated an eradication and management time-scale pattern diagram. Relatedness within a colony using microsatellite markers was effectively zero, whereas relatedness estimated by multilocus DNA fingerprinting markers was relatively high. Specifically, relatedness of recently invaded populations was estimated at nearly 0.3. From the results of behavioral bioassays on the invading populations of the Argentine ant, all colonies except the Kobe supercolonies did not show clearly aggressive behaviors toward workers belonging to other colonies, even when distantly located. Because they are critical factors for eradicating and managing invasive organisms, we assessed the relationships among kin relatedness using multilocus DNA fingerprinting and microsatellite markers, with aggressiveness, in 2011 and 2012, including the establishment durations, and distances among supercolonies. A generalized linear model (GLM) analysis, with establishment durations as an explanatory variable, strongly contributed to explaining estimated relatedness from the two methods. Specifically, models using kin relatedness for both multilocus DNA fingerprinting and microsatellite markers provided the strongest contribution to explaining the establishment durations. Within 3 yr after establishment in a native area, eradication is possible because of their low genetic diversity and small colony size. After 15 yr, eradication will be more difficult, but it is preferable to just monitor the impact for a nonnative ecosystem.

Spectral study of metabolism-based autofluorescence and white-light reflectance for endoscopic tumor imaging

Metabolism-based autofluorescence redox imaging is one of the promising options for non-invasive screening of digestive tumors. In this paper, autofluorescence from fluorescent coenzymes such as NADH and FAD related to cellular metabolism as well as total hemoglobin and oxygen saturation are analyzed based on a point spectrum. As a redox index based on the metabolism, the ratio of the 450nm-490nm fluorescence intensities for 365nm and 405nm excitation wavelengths (F365/F405) is used. Although F365/F405 is a good index in many samples, inversion and weakened contrast are observed. A Simplified models with and without collagen based on Lambert-Beer law are built to explain how F365/F405 depicts the tumor region.

Embryonic MicroRNA-369 Controls Metabolic Splicing Factors and Urges Cellular Reprograming

Noncoding microRNAs inhibit translation and lower the transcript stability of coding mRNA, however miR-369 s, in aberrant silencing genomic regions, stabilizes target proteins under cellular stress. We found that in vitro differentiation of embryonic stem cells led to chromatin methylation of histone H3K4 at the miR-369 region on chromosome 12qF in mice, which is expressed in embryonic cells and is critical for pluripotency. Proteomic analyses revealed that miR-369 stabilized translation of pyruvate kinase (Pkm2) splicing factors such as HNRNPA2B1. Overexpression of miR-369 stimulated Pkm2 splicing and enhanced induction of cellular reprogramming by induced pluripotent stem cell factors, whereas miR-369 knockdown resulted in suppression. Furthermore, immunoprecipitation analysis showed that the Argonaute complex contained the fragile X mental retardation-related protein 1 and HNRNPA2B1 in a miR-369-depedent manner. Our findings demonstrate a unique role of the embryonic miR-369-HNRNPA2B1 axis in controlling metabolic enzyme function, and suggest a novel pathway linking epigenetic, transcriptional, and metabolic control in cell reprogramming.

Three-dimensional positioning and control of colloidal objects utilizing engineered liquid crystalline defect networks

Topological defects in liquid crystals not only affect the optical and rheological properties of the host, but can also act as scaffolds in which to trap nano or micro-sized colloidal objects. The creation of complex defect shapes, however, often involves confining the liquid crystals in curved geometries or adds complex-shaped colloidal objects, which are unsuitable for device applications. Using topologically patterned substrates, here we demonstrate the controlled generation of three-dimensional defect lines with non-trivial shapes and even chirality, in a flat slab of nematic liquid crystal. By using the defect lines as templates and the electric response of the liquid crystals, colloidal superstructures are constructed, which can be reversibly reconfigured at a voltage as low as 1.3 V. Three-dimensional engineering of the defect shapes in liquid crystals is potentially useful in the fabrication of self-healing composites and in stabilizing artificial frustrated phases.

Topological defects can be used not only to modify the properties of liquid crystals but also as scaffolds to build new structures by trapping particles. Here, Yoshida et al. construct three-dimensional colloidal superstructures in a nematic host, which are reconfigurable in an electric field.

Pyruvate kinase M2, but not M1, allele maintains immature metabolic states of murine embryonic stem cells

The M2 isoform of pyruvate kinase, the final rate-limiting enzyme of aerobic glycolysis, is expressed during embryonic development. In contrast, the M1 isoform is expressed in differentiated cells due to alternative splicing. Here we investigated murine embryonic stem cells (ESCs) with Pkm1 or Pkm2 knock-in alleles. Pkm1 allele knock-in resulted in excessive oxidative phosphorylation and induced the formation of cysteine-thiol disulfide-dependent complexes of forkhead box class-O (FOXO) transcription factors, which resulted in altered endoderm differentiation. In contrast, Pkm2 knock-in induced synthesis of a methylation-donor, S-adenosylmethionine, and increased unsaturated eicosanoid groups, which contributed to the redox control and maintenance of ESC undifferentiated status. Because PKM2 is also a critical enzyme for the cancer-specific Warburg effect, our results demonstrate an important role for the Pkm2 allele in establishing intracellular redox conditions and modulating PKM1-dependent oxidative phosphorylation events to achieve an appropriate ESC differentiation program.

Immunohistochemical expression of fibrillin-1 and fibrillin-2 during tooth development

BACKGROUND AND OBJECTIVE

Oxytalan fibers are categorized as a microfibril assembly without elastin deposition, and are unique components in the periodontal ligament (PDL). However, little is known about their formation during PDL development. To clarify the mechanisms of oxytalan fiber formation in developing PDL, we performed immunohistochemical analysis to detect the direct expression of fibrillin-1 and fibrillin-2, which are major components of microfibrils.

MATERIAL AND METHODS

Frozen sections of lower molars from mice at several stages of growth were prepared without chemical fixation and decalcification using the film transfer method. Immunostaining was performed with anti-fibrillin-1 and -2, and anticytokeratin antibodies.

RESULTS

Fibrillin-1 was not expressed in the dental follicle during the crown forming stage. At postneonatal day 9, fibrillin-1 expression started with meshwork appearance between the epithelial cells from Hertwig's epithelial root sheath at the root dentin surface. Fibirillin-2 was detected much earlier than fibrillin-1 expression. Fibrillin-2 was expressed with a liner appearance, running parallel to the root axis in PDL, and was partially co-expressed with cytokeratin 14 expression in Hertwig's epithelial root sheath. Furthermore, we detected both fibrillin-1 and fibrillin-2 expression in human PDL. Fibrillin-1 was detected in fibers with a vertically oriented root axis in PDL. Fibrillin-2 was widely expressed in PDL, including around the epithelial cell rests of Malassez. Fibrillin-1 and fibrillin-2 were clearly co-expressed in thick fiber structures in human PDL.

CONCLUSION

Our results suggest that both fibrillin-1 and fibrillin-2 expression is required to form thick oxytalan fibers in PDL. Based on the expression patterns for fibrillin-1 and fibrillin-2, they have different functions during tooth root and PDL development. Early expression of fibrillin-2 may regulate dental epithelial cell behavior during root and PDL development.

SCGB2A1 is a novel prognostic marker for colorectal cancer associated with chemoresistance and radioresistance

We recently showed that liver metastatic tissue from patients with colorectal cancer (CRC) was a useful model for identifying novel, hypoxia-inducible genes and prognostic markers. We showed that the expression of secretoglobin, family 2A, member 1 (SCGB2A1) was a potential prognostic factor for CRC. Here, we further evaluated the prognostic impact and function of SCGB2A1 in 222 patients with CRC. The impact of SCGB2A1 expression on disease-free survival (DFS) and overall survival (OS) was assessed with mRNA expression profiling. The function of SCGB2A1 was analyzed by evaluating mRNA expression profiles in cells derived from patients with CRC and by testing the effects of transfecting SCGB2A1 into different CRC-derived cell lines. We evaluated the effects of SCGB2A1 on proliferation, chemosensitivity, radiation sensitivity and sphere formation. Univariate and multivariate analyses indicated that the expression of SCGB2A1 was an independent prognostic factor for CRC (p<0.05), together with lymph node metastasis (p<0.05). Enforced expression of SCGB2A1 in CRC-derived cell lines promoted proliferation (DLD1, SW480 and LoVo cells; p<0.05), decreased chemosensitivity to 5-fluorouracil and oxaliplatin (DLD1 and SW480 cell lines; p<0.05), and significantly increased the viability of irradiated cells (DLD1, SW480 and LoVo cell lines; p<0.05). SCGB2A1 expression was also correlated to cancer stemness-related genes (Wnt, Zeb1 and Twist). Consistent with this correlation, SCGB2A1 expressing cells (SW480) showed increased sphere formation (p<0.05). These results indicated that SCGB2A1 represented a novel, prognostic factor for CRC, and that expression of SCGB2A1 correlated with chemoresistance, radioresistance and cancer cell stemness.

[Cancer stem cells depend on their own niche]

It is considered that cancer stem cells have the same characteristics as normal stem cells, such as drug-resistance, self-renewal, differentiation, and tissue-formation. Normal stem cells depend on their surroundings, a niche. Cancer stem cells may also depend on their own niche. Because cancer stem cells are resistant to present remedies, it is important to find a remedy targeting cancer stem cells. The remedy must not only target cancer stem cells themselves but also target the niche surrounding the cancer stem cells.

Adipose-derived mesenchymal stem cells and regenerative medicine

Adipose tissue-derived mesenchymal stem cells (ADSCs) are multipotent and can differentiate into various cell types, including osteocytes, adipocytes, neural cells, vascular endothelial cells, cardiomyocytes, pancreatic β-cells, and hepatocytes. Compared with the extraction of other stem cells such as bone marrow-derived mesenchymal stem cells (BMSCs), that of ADSCs requires minimally invasive techniques. In the field of regenerative medicine, the use of autologous cells is preferable to embryonic stem cells or induced pluripotent stem cells. Therefore, ADSCs are a useful resource for drug screening and regenerative medicine. Here we present the methods and mechanisms underlying the induction of multilineage cells from ADSCs.

Depletion of JARID1B induces cellular senescence in human colorectal cancer

The global incidence of colorectal cancer (CRC) is increasing. Although there are emerging epigenetic factors that contribute to the occurrence, development and metastasis of CRC, the biological significance of epigenetic molecular regulation in different subpopulations such as cancer stem cells remains to be elucidated. In this study, we investigated the functional roles of the H3K4 demethylase, jumonji, AT rich interactive domain 1B (JARID1B), an epigenetic factor required for the continuous cell growth of melanomas, in CRC. We found that CD44(+)/aldehyde dehydrogenase (ALDH)(+) slowly proliferating immature CRC stem cell populations expressed relatively low levels of JARID1B and the differentiation marker, CD20, as well as relatively high levels of the tumor suppressor, p16/INK4A. Of note, lentiviral‑mediated continuous JARID1B depletion resulted in the loss of epithelial differentiation and suppressed CRC cell growth, which was associated with the induction of phosphorylation by the c‑Jun N‑terminal kinase (Jnk/Sapk) and senescence‑associated β‑galactosidase activity. Moreover, green fluorescent‑labeled cell tracking indicated that JARID1B‑positive CRC cells had greater tumorigenicity than JARID1B‑negative CRC cells after their subcutaneous inoculation into immunodeficient mice, although JARID1B‑negative CRC cells resumed normal growth after a month, suggesting that continuous JARID1B inhibition is necessary for tumor eradication. Thus, JARID1B plays a role in CRC maintenance. JARID1B may be a novel molecular target for therapy‑resistant cancer cells by the induction of cellular senescence.

Eradication of therapy-resistant cancer cells in gastrointestinal organs

Early stages of cancer are curable by surgical removal of the primary lesions, however, more advanced cases are often refractory to therapeutic approaches and are more commonly life-threatening, primarily due to cancer metastasis in gastrointestinal cancers. Such biological events are collectively characterized as tumor heterogeneity, the cause of which is the existence of cancer stem cells. To improve cancer survival, therapy-resistant cancer cells should be eradicated. To this end, recent rapid progress in medical science, such as innovative medical technologies including cancer reprogramming, RNA pharmacology and drug delivery systems, all of which effectively target cancer stem cells, has facilitated this objective.

Dehydroxymethylepoxyquinomicin (DHMEQ), a novel NF-kappaB inhibitor, inhibits allergic inflammation and airway remodelling in murine models of asthma

BACKGROUND

Dehydroxymethylepoxyquinomicin (DHMEQ) is a newly developed compound that inhibits nuclear factor κB activation and is reported to ameliorate animal models of various inflammatory diseases without significant adverse effects. Because nuclear factor κB is a transcription factor that plays a critical role in the pathophysiology of asthma, DHMEQ may be of therapeutic benefit in asthma.

OBJECTIVE

The purpose of this study was to evaluate the effects of DHMEQ on airway inflammation and remodelling in murine models of asthma.

METHODS

The BALB/c mice were sensitized and then challenged acutely or chronically with ovalbumin and administered DHMEQ intraperitoneally before each challenge. Inflammation of airways, lung histopathology and airway hyper responsiveness to methacholine challenge were evaluated. In addition, the effect of DHMEQ on production of cytokines and eotaxin-1 by murine splenocytes, human peripheral blood mononuclear cells and bronchial epithelial cells was investigated.

RESULTS

Airway hyper responsiveness was ameliorated in both acutely and chronically challenged models by treatment with DHMEQ. DHMEQ significantly reduced eosinophilic airway inflammation and levels of Th2 cytokines in bronchoalveolar lavage fluid in the acute model. It also inhibited parameters of airway remodelling including mucus production, peribronchial fibrosis and the expression of α-smooth muscle actin. Moreover, the production of Th2 cytokines from murine splenocytes and human peripheral blood mononuclear cells and the production of eotaxin-1 by bronchial epithelial cells were inhibited by DHMEQ.

CONCLUSIONS AND CLINICAL RELEVANCE

These results indicate that DHMEQ inhibits allergic airway inflammation and airway remodelling in murine models of asthma. DHMEQ may have therapeutic potential in the treatment of asthma.

Transcriptomic study of dormant gastrointestinal cancer stem cells

We previously discovered the coexistence of dormant and proliferating cancer stem cells (CSCs) in gastrointestinal cancer, which leads to chemoradiation resistance. CD13-/CD90+ proliferating liver CSCs are sensitive to chemotherapy, and CD13+/CD90- dormant CSCs have a limited proliferation ability, survive in hypoxic areas with reduced oxidative stress, and relapse and metastasize to other organs. In such CD13+ dormant cells, non-homologous end-joining, an error-prone repair mechanism, is dominant after DNA damage, whereas high-fidelity homologous recombination is apparent in CD13- proliferating cells, suggesting the significance of dormancy as an essential protective mechanism of therapy resistance. However, this mechanism may also play a role in the generation and accumulation of heterogeneity during cancer progression, although the exact mechanism remains to be understood. Through transcriptomic study, we elucidated the underlying epigenetic mechanism for malignant behavior of dormant CSCs, i.e., simultaneous activation of several pathways including EZH2- and TP53-related proteins in response to microRNA101, suggesting that a pharmacogenomic approach would open an era to novel molecular targeting cancer therapy.

Extravascular injection of sclerotic agents does not affect vessels in the rat: experimental implications for percutaneous sclerotherapy of arteriovenous malformations

OBJECTIVES

Sclerotherapy is useful for the treatment of arteriovenous vascular malformations. However, intravascular administration of sclerotic agents into small arteriovenous niduses is often difficult. Extravascular administration of sclerotic agents causes reduction of vascular flow on Doppler echo during clinical sclerotherapy. Therefore, we aimed to investigate whether the extravascular injection of sclerotic agents affects tiny vessels.

DESIGN

Animal study.

MATERIALS

The effect of extravascular injection of sclerotic agents on vessels was investigated using rat femoral and superficial inferior epigastric vessels.

METHODS

After surgical exposure of vessels, absolute ethanol, 5% ethanolamine oleate and 3% polidocanol were injected into perivascular surrounding tissues, and their effect on vessels was evaluated after 14 days using histology and coloured silicone rubber injection.

RESULTS

The integrity of the vascular lumen, endothelial cells and vascular patency were not affected by injection of sclerotic agents.

CONCLUSIONS

Attenuation of vascular flow of an arteriovenous shunt after extravascular injection of sclerotic agents is transient and/or trivial and does not cause disruption of vessels. Therefore, sclerotic agents should be delivered to obtain sufficient destruction of arteriovenous malformation lesions and blood flow.

Genotoxic therapy stimulates error-prone DNA repair in dormant hepatocellular cancer stem cells

Previous studies have described distinct dormant and proliferating populations of cancer stem cells in hepatocellular carcinoma. The CD13 protein is involved in the scavenging of reactive oxygen species through the glutathione reductase pathway and is associated with resistance to chemotherapy. Whereas CD13(-) proliferating cancer stem cells are sensitive to chemotherapy, CD13(+) dormant cancer stem cells are associated with the development of resistance to chemotherapy. CD13(+) cells in hypoxic areas of the tumour survive chemotherapy, leading to subsequent disease relapse and metastasis. Whether CD13(+) dormant cells simply resume proliferation following therapy or whether they also acquire greater malignant potential, remains unknown. The mechanisms involved also remain unclear. In the present study, we investigated the repair of DNA damage in CD13(+) dormant and CD13(-) proliferating cells. Total RNA was extracted from tissues, and quantitative real-time polymerase chain reaction (PCR) was performed for specific genes and GAPDH following PCR. Products were then subjected to a temperature gradient of 55-95°C with continuous fluorescence monitoring to generate a melting curve. Cells were incubated with primary antibodies, washed twice, incubated with fluorescent-labelled secondary antibodies for 30 min on ice and analyzed by flow cytometry. The results revealed that the repair of DNA damage in CD13(+) dormant cells occurs predominantly through non-homologous end-joining, a repair process that is error-prone, whereas CD13(-) proliferating cells primarily utilise high-fidelity homologous recombination for DNA repair. These data indicate that not only is dormancy a protective mechanism for cancer stem cells to survive therapy, but it also enhances the generation and accumulation of mutations following DNA damage. Therefore, the CD13(+) dormant cancer stem cells must be eradicated fully to achieve complete remission of cancer.

Dicer 1, ribonuclease type III modulates a reprogramming effect in colorectal cancer cells

Complete cell reprogramming can be achieved by the introduction of specific transcription factors, Oct4 [also known as POU class 5 homeobox 1 (Pou5f1)]; sex-determining region Y (SRY)-box 2 (Sox2); Kruppel-like factor 4 (Klf4); and myelocytomatosis viral oncogene homolog (c-Myc), into terminally differentiated mouse somatic fibroblasts. This reprogramming process may be accelerated or suppressed by various factors, including microRNAs (miRNAs). Introduction of these transcription factors or miRNAs considerably modifies the malignant phenotype of cancer cells. We studied the effect of introducing these transcription factors into two distinct colorectal cancer (CRC) cell lines, HCT116 and DLD-1, in the presence and absence of Dicer 1, ribonuclease type III (Dicer1), a critical miRNA processing enzyme. We assessed cell reprogramming based on the number of cells exhibiting alkaline phosphatase staining and an increase in embryonic stem cell-like gene expression, indicating the return of cells to an immature state. Dicer1-deficient CRC cells showed a reduced number of alkaline phosphatase-positive reprogrammed cells than wild-type (WT) cells. Before reprogramming, endogenous expression of an immature carbohydrate epitope, TRA-1-60, was high in Dicer1-deficient CRC cells, whereas after reprogramming, the expression of this epitope was increased in Dicer1-sufficient more than in Dicer1-deficient CRC cells. Our data demonstrate the critical role of miRNAs in the reprogramming process and determination of a differentiated phenotype of CRC cells.

Usefulness of an anesthetic conserving device (AnaConDa™) in sevoflurane anesthesia

BACKGROUND

The anesthetic conserving device (AnaConDaTM) is a disposable vaporizer that can save consumption of inhalational anesthetic used in low sevoflurane concentration. This study was performed to investigate whether AnaConDa when used at high sevoflurane concentration (1.5% to 2.0%) could save sevoflurane consumption and hasten emergence from anesthesia without any adverse effects.

METHODS

Thirty patients for ear surgery were equally divided into AnaConDa and control groups. Anesthesia was induced with intravenous anesthetics. After intubation sevoflurane inhalation started by infusion at 25 mL/h in the AnaConDa group and by inhalation of 2.0% (conventional vaporizer setting) in the control group. During anesthesia, end-tidal sevoflurane concentration was kept between 1.5 and 2.0% in both groups. The time to first detection of end-tidal sevoflurane, the time to sevoflurane concentration reached 1.5%, sevoflurane consumption, and emergence time were compared between the two groups. Adverse effects were checked.

RESULTS

Sevoflurane consumption was smaller, time to first detection of end-tidal sevoflurane was longer, time to sevoflurane concentration reached 1.5% was longer, emergence time was shorter, and decrease of end-tidal sevoflurane concentration after stop of administration was faster in the AnaConDa group significantly. Clear Water accumulation with no smell in the filter was observed in 12 of 15 patients in the AnaConDa group.

CONCLUSION

In general anesthesia with sevoflurane 1.5% to 2.0%, AnaConDa could save sevoflurane consumption and fasten emergence from anesthesia compared to conventional vaporizer, while water accumulation in the filter should be cautioned.

Hypoxia and TP53 deficiency for induced pluripotent stem cell-like properties in gastrointestinal cancer

Induced pluripotent stem (iPS)-like cancer cells (iPC) by the introduction of defined transcription factors reduce the prevalence of the malignant phenotype of digestive system cancer cells, but the induction efficiency is low. The role of hypoxia and TP53 deficiency in iPC cell generation remain unclear. Cellular reprogramming was performed by retroviral infection with OCT3/4, SOX2, KLF4 and c-MYC of wild-type HCT116 colorectal cancer cells and mutant TP53-deficient HCT116 cells. Cells were cultured in normoxia (21% O2) or hypoxia (5% O2) for 30 days after transduction, and the response to hypoxia and comparison of cellular proliferation, invasion and tumourigenesis before and after iPC cell generation were studied. iPC cell generation from wild-type HCT116 cells in hypoxia was approximately 4-times greater than in normoxia (p<0.05), and TP53 deficiency increased conversion efficiency significantly in normoxia (p<0.05). Significant involvement of hypoxia-inducible factors was observed in an immature carbohydrate epitope, Tra-1-60+, colony formation. Generated iPC cells exhibited multi-differentiation potential. Although the iPC cells in hypoxia exhibited reduced proliferation, invasiveness and tumourigenicity, TP53 deficiency in iPC cells resulted in higher tumourigenicity than in wild-type cells. Both hypoxia and TP53 deficiency increase iPC cell generation. TP53 deficiency can also result in deleterious mutations, whereas hypoxia may impact molecular targets of epigenome normalisation.

Reprogramming of gastrointestinal cancer cells

Cell reprogramming reverts cells to multipotent, preprogrammed states by re-establishing epigenetic markers. It can also induce considerable malignant phenotype modification. Because key events in cancer relapse and metastasis, including epithelial-mesenchymal transition phenotypes, are regulated primarily by reversible and transient epigenetic modifications rather than the accumulation of irreversible and stable genetic abnormalities, studying dynamic mechanisms regulating these biological processes is important. Transcription factors for induced pluripotent stem cells and non-coding microRNAs allow pluripotent phenotype induction. We present the current knowledge of the possible applications of cell reprogramming in reducing aggressive phenotype expression, which can induce tumor cell hibernation and maintain appropriate phenotypes, thereby minimizing relapse and metastasis after surgical resection of gastrointestinal cancer.

Measurement of separate cosmic-ray electron and positron spectra with the fermi large area telescope

We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting Earth's shadow, which is offset in opposite directions for opposite charges due to Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 and 200 GeV. We confirm that the fraction rises with energy in the 20-100 GeV range. The three new spectral points between 100 and 200 GeV are consistent with a fraction that is continuing to rise with energy.

Constraining dark matter models from a combined analysis of Milky Way satellites with the Fermi Large Area Telescope

Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10(-26)  cm3  s(-1) at 5 GeV to about 5×10(-23)   cm3  s(-1) at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section (∼3×10(-26)  cm3  s(-1) for a purely s-wave cross section), without assuming additional boost factors.