Epidemiology of colonic diverticula and recent advances in the management of colonic diverticular bleeding

There is the East-West paradox in prevalence and phenotype of colonic diverticula, but colonic diverticular bleeding (CDB) is the most common cause of acute lower gastrointestinal bleeding worldwide. Death from CDB can occur in elderly patients with multiple comorbidities, thus the management of CDB is clinically pivotal amid the aging populations in the East and West. Colonoscopy is the key modality for managing the condition appropriately; however, conventional endoscopic hemostasis by thermal coagulation and clipping cannot achieve the expected results of preventing early rebleeding and conversion to intensive intervention by surgery or transcatheter arterial embolization. Ligation therapy by endoscopic band ligation or endoscopic detachable snare ligation has emerged recently to enable more effective hemostasis for CDB, with an early rebleeding rate of approximately 10% and very rare conversion to intensive intervention. Ligation therapy might in turn reduce long-term rebleeding rates by eliminating the target diverticulum itself. Adverse events have been reported with ligation therapy including diverticulitis of the ascending colon in less than 1% of cases and perforation of the sigmoid colon in a few cases, thus more data are necessary to verify the safety of ligation therapy. Endoscopic hemostasis is indicated only for diverticulum with stigmata of recent hemorrhage (SRH), but the detection rates of SRH are relatively low. Therefore, efforts to increase detection are also key for improving CDB management. Urgent colonoscopy and triage by early contrast-enhanced computed tomography may be candidates to increase detection but further data are necessary in order to make a conclusion.     

Anatomical correlates of quality of life: Evidence from voxel‐based morphometry

Quality of life (QOL) has been defined in many ways, and these definitions usually emphasize happiness and satisfaction with life. Health‐related problems are known to cause lower QOL. However, the neural mechanisms underlying individual differences in QOL measured by questionnaire (QOLMQ) in young healthy subjects are unknown. QOL is essential to our well‐being, and investigation of the neural mechanisms underlying QOL in uncompromised subjects is obviously of great scientific and social interest. We used voxel‐based morphometry to investigate the association between regional gray matter volume (rGMV) and QOLMQ across the brain in healthy young adults (age, 21.4 ± 1.8 years) men (n = 88) and women (n = 68) in humans. We found significant negative relationships between QOLMQ and rGMV in a region in the left rostrolateral prefrontal cortex and regions in the dorsal part of the anterior cingulate gyrus and contingent cingulate regions. These findings show that structural variations in regions associated with processing of negative emotions such as fear and anger as well as those associated with evaluation of internally generated information are associated with QOLMQ. These findings suggest that these processes might be related to QOLMQ in healthy young adults. Hum Brain Mapp 35:1834–1846, 2014. © 2013 Wiley Periodicals, Inc.     

Evaluation of DNA and RNA quality from archival formalin‐fixed paraffin‐embedded tissue for next‐generation sequencing – Retrospective study in Japanese single institution

Genetic analysis on formalin‐fixed paraffin‐embedded (FFPE) tissue specimens has become a mainstream method, from conventional direct sequencing to comprehensive analysis using next‐generation sequencing (NGS). In this study, we evaluated the quality of DNA and RNA extracted from FFPE sections, derived from surgical specimens of different tumor types. Electrophoresis was performed using a 4200 TapeStation to evaluate DNA and RNA fragmentation. DNA Ct values were higher and significantly increased over a period of 4 years compared with those from cell lines or frozen tissues. The RNA integrity number equivalent (RIN) ranged from 1 to 4.1 and DV200 ranged from 7.3 to 81%. Twelve of the 108 cases were analyzed by NGS using the AmpliSeq Cancer HotSpot Panel v2 on a Miniseq system. A sufficient number of reads and coverage were obtained in all cases. Our results revealed that NGS analysis was sufficient for FFPE‐derived DNA within 4 years of preservation. Conversely, approximately 20% of the RNA derived from FFPE within 4 years from the collection could be inappropriate for gene analysis based on RIN and DV200. It was suggested that FFPE would be adequate for genetic analysis, although it is desirable to store frozen specimens for the tumor tissues to be subjected to genetic analysis.     

Myocardial stiffness is determined by ventricular fibrosis,but not by compensatory or excessive hypertrophy in hypertensive heart

OBJECTIVES: Diastolic dysfunction that determines symptoms and prognosis in patients with systolic dysfunction causes heart failure even in the absence of systolic dysfunction. Our recent studies have suggested that myocardial stiffening is likely to play a crucial role in triggering deleterious cardiac disorder. This study investigated differential contribution of left ventricular (LV) hypertrophy and fibrosis to myocardial stiffening in the pressure-overloaded heart. METHODS: Dahl-Iwai salt-sensitive rats fed on high-salt diet since 7 weeks transit to congestive heart failure at 20 weeks following development of hypertension, LV hypertrophy and fibrosis, and 20 such rats were divided into three groups: rats treated with angiotensin II type 1 receptor antagonist from 8 weeks (n=7), rats treated with calcineurin inhibitor from 8 weeks (n=6), and untreated rats (n=7). RESULTS: Administration of angiotensin II type 1 receptor antagonist and calcineurin inhibitor did not affect blood pressure and allowed the development of compensatory hypertrophy. However, in contrast to the untreated rats, additive and excessive LV hypertrophy was not observed in either of the treated rats. The blockade of angiotensin II kept LV hydroxyproline content, a ratio of type I to type III collagen mRNA levels, collagen solubility and myocardial stiffness constant at the normal level; however, the calcineurin inhibition failed. CONCLUSIONS: Myocardial stiffening may be attributed to progressive collagen accumulation, collagen phenotype shift and enhanced collagen cross-linking, but not to either compensatory LV hypertrophy or LV hypertrophy that progresses from the compensatory stage.     

Conformational alterations in unidirectional ion transport of a light-driven chloride pump revealed using X-ray free electron lasers

Light-driven chloride-pumping rhodopsins actively transport anions, including various halide ions, across cell membranes. Recent studies using time-resolved serial femtosecond crystallography (TR-SFX) have uncovered the structural changes and ion transfer mechanisms in light-driven cation-pumping rhodopsins. However, the mechanism by which the conformational changes pump an anion to achieve unidirectional ion transport, from the extracellular side to the cytoplasmic side, in anion-pumping rhodopsins remains enigmatic. We have collected TR-SFX data of Nonlabens marinus rhodopsin-3 (NM-R3), derived from a marine flavobacterium, at 10-µs and 1-ms time points after photoexcitation. Our structural analysis reveals the conformational alterations during ion transfer and after ion release. Movements of the retinal chromophore initially displace a conserved tryptophan to the cytoplasmic side of NM-R3, accompanied by a slight shift of the halide ion bound to the retinal. After ion release, the inward movements of helix C and helix G and the lateral displacements of the retinal block access to the extracellular side of NM-R3. Anomalous signal data have also been obtained from NM-R3 crystals containing iodide ions. The anomalous density maps provide insight into the halide binding site for ion transfer in NM-R3.

Microbial ion-pumping rhodopsins are integral membrane proteins that actively transport ions across membranes upon light stimulation (1). Bacteriorhodopsin (bR) and halorhodopsin (HR) are well-known microbial ion-pumping rhodopsins found in halophilic archaea (2, 3). bR is a light-driven outward proton pump and HR is a light-driven inward anion pump, specific for chloride ion. Microbial ion-pumping rhodopsins possess common structural features consisting of seven α-helices with an all-trans retinal covalently bound to a lysine residue as the chromophore, despite the transport of different ions (4). The retinal undergoes photoisomerization from the all-trans to 13-cis configuration, which initiates the photocycle accompanied by several intermediates to export ions (4, 5). Its light-controllable function is suitable for optogenetics applications for manipulating cells, such as neurons, by changing the ion concentration inside or outside the membrane (6, 7). In fact, microbial rhodopsins, including channelrhodopsins and HRs, are employed as optogenetic tools (8–10).Nonlabens marinus rhodopsin-3 (NM-R3) is a light-driven chloride pump recently discovered in a marine flavobacterium (11). It is a distinct chloride pump from HRs and shows low amino acid sequence homology with HRs (11). To date, HR-type chloride pumps have been found in haloarchaea, marine bacteria, and cyanobacteria, including Halobacterium salinarum, Natronomonas pharaonis, and Mastigocladopsins repens, with sequence identities of 20%, 21%, and 20% to NM-R3, respectively (3, 12–15). Interestingly, NM-R3 has higher sequence identity (36%) to Krokinobacter rhodopsin 2 (KR2), a sodium pump found in Krokinobacter eikastus (16). NM-R3 possesses a unique NTQ motif (Asn98, Thr102, Gln109) in the third helix (helix C), which corresponds to key residues (DTD motif, Asp85, Thr89, Asp96) for proton transport in bR (11, 17, 18) (SI Appendix, Table S1). Asp85 acts as the primary proton acceptor of bR from the protonated Schiff-base (PSB), with assistance from Thr89 and Asp96, which is the proton donor (5, 17, 18). HRs from haloarchaea have a highly conserved TSA (Thr, Ser, Ala) motif, while the Ala residue is replaced by Asp in HR from cyanobacteria (19). In the X-ray crystal structure of NM-R3 (SI Appendix, Fig. S1A), a chloride ion located between the PSB and Asn98 (SI Appendix, Fig. S1B) is stabilized by the positive charge of the PSB (20). The position of this chloride ion is similar to those in the H. salinarum HR and N. pharaonis HR (NpHR) structures except for Thr and Ser, which correspond to Asn98 and Thr102 in NM-R3, respectively (20–22). Several amino acid residues around the retinal, including Arg95, Trp99, Trp201, and Asp231, are highly conserved among ion-pumping rhodopsins. Previous spectroscopic studies suggested that NM-R3 displays a similar sequence of intermediates, with K-, L-, N-, and O-like species, as in other HRs (23) (Fig. 1A). Recently, intermediate structures of NM-R3 obtained by low-temperature trapping X-ray crystallography and serial femtosecond crystallography (SFX) have been reported (24, 25). However, the detailed ion-pump mechanism still remains unclear, due to the lack of dynamic structures of anion transport at atomic resolution.Open in a separate windowFig. 1.TR-visible absorption spectroscopy for microcrystals. (A) Photocycle model of NM-R3 in the 1 M NaCl buffer solution (23). (B) TR difference spectra ΔA upon the 532-nm excitation. The difference was calculated by subtracting the spectrum of NM-R3. (C) Global fitting analysis with two exponentials. The A₁ and A₂ amplitude spectra correspond to the differences of [ΔA_O – ΔA_{10 µs}] and [ΔA_{200 ms} − ΔA_O], respectively. Here, ΔA_O represents the difference spectrum of the O intermediate minus NM-R3. (D) The isomeric forms of the retinal chromophore in bacterial-type rhodopsins.Time-resolved serial femtosecond crystallography (TR-SFX) is a powerful tool for visualizing reactions and motions in proteins at the atomic level (26–28). In SFX, myriads of microcrystals are continuously injected by a sample injector into an irradiation point of X-ray free electron lasers (XFELs) at room temperature, thus providing diffraction patterns before the onset of radiation damage by the intense X-ray pulse. Combined with a visible-light pump laser for reaction initiation, TR-SFX has been applied to light-driven ion pumps to observe the structural dynamics during the ion transfer. While TR-SFX has revealed femto-to-millisecond structural dynamics in light-driven cation pumps, including bR and KR2 (29–31), TR-SFX studies of anion pumps have been limited to early-stage structures adopted at picoseconds after light illumination (32). In addition, although NM-R3 pumps a chloride ion (Cl⁻) as a physiological substrate, it can also transport bromide (Br⁻), iodide (I⁻), and other anions from the extracellular side to the cytoplasmic side (23). I⁻ or Br⁻ serves as a marker for tracking the positions of ions, due to the greater number of electrons, whereas Cl⁻ is less distinguishable in X-ray crystallography. Therefore, TR-SFX experiments using I⁻ or Br⁻ are expected to directly visualize the process of ion transport.Here, we report the conformational alterations in NM-R3 during Br⁻ or I⁻ pumping, obtained by both TR-SFX and time-resolved spectroscopy of crystals. The resulting sequence of movements in NM-R3 demonstrates how the chloride pump transports anions with a large ionic radius and prevents the backflow of anions from the cytoplasmic side.     

Nematode ascarosides attenuate mammalian type 2 inflammatory responses

Mounting evidence suggests that nematode infection can protect against disorders of immune dysregulation. Administration of live parasites or their excretory/secretory (ES) products has shown therapeutic effects across a wide range of animal models for immune disorders, including asthma. Human clinical trials of live parasite ingestion for the treatment of immune disorders have produced promising results, yet concerns persist regarding the ingestion of pathogenic organisms and the immunogenicity of protein components. Despite extensive efforts to define the active components of ES products, no small molecules with immune regulatory activity have been identified from nematodes. Here we show that an evolutionarily conserved family of nematode pheromones called ascarosides strongly modulates the pulmonary immune response and reduces asthma severity in mice. Screening the inhibitory effects of ascarosides produced by animal-parasitic nematodes on the development of asthma in an ovalbumin (OVA) murine model, we found that administration of nanogram quantities of ascr#7 prevented the development of lung eosinophilia, goblet cell metaplasia, and airway hyperreactivity. Ascr#7 suppressed the production of IL-33 from lung epithelial cells and reduced the number of memory-type pathogenic Th2 cells and ILC2s in the lung, both key drivers of the pathology of asthma. Our findings suggest that the mammalian immune system recognizes ascarosides as an evolutionarily conserved molecular signature of parasitic nematodes. The identification of a nematode-produced small molecule underlying the well-documented immunomodulatory effects of ES products may enable the development of treatment strategies for allergic diseases.

Parasitic nematodes are associated with almost all groups of vertebrates, and nearly one-third of the human population is infected with these helminths (1). Their omnipresence is in part due to their ability to modulate host immune responses to prevent immune attack and expulsion (2). The elimination of nematode infections has been proposed as a possible cause of the increased incidence of autoimmune disorders and allergic diseases in developed countries (3), based on epidemiological data showing a correlation between the decline in helminth infection and the rise in allergic and autoimmune diseases, including asthma, multiple sclerosis (MS), type 1 diabetes, and inflammatory bowel diseases (IBDs) (4).The administration of live nematodes or their excretory/secretory (ES) products has shown therapeutic effects across a wide range of animal models for these immune disorders (5–8). The US Food and Drug Administration recently approved live helminth administration as an investigational drug for the treatment of immune disorders, and relevant human clinical trials are ongoing (9). Despite mounting evidence that helminths have significant therapeutic potential, we do not yet have a comprehensive understanding of the molecules that underlie their immunomodulatory effects; and, in particular, the possible relevance of low-molecular-weight components of ES products has remained largely unexplored.A wide range of nematodes, including many parasitic species, produce ascarosides, a family of small-molecule signals based on glycosides of the dideoxysugar ascarylose (10). Ascarosides have not yet been identified in any other animal phylum, suggesting that they may be a nematode-specific class of small molecules (SI Appendix, Fig. S1A). The first ascaroside-based signaling molecules were identified in the free-living model nematode Caenorhabditis elegans (11, 12). Ascarosides regulate almost every aspect of C. elegans life history, including diapause (dauer) induction, aging, mate finding, and aggregation (11, 12). Subsequently, ascarosides have been shown to be detected by organisms other than nematodes, such as nematophagous fungi that set traps to capture and digest nematodes (13). The perception of ascarosides is sufficient to trigger trap formation in these fungi, demonstrating their longstanding evolutionary association with nematodes. Furthermore, ascarosides produced by plant-pathogenic nematodes have been shown to trigger innate immune responses in monocot and dicot plants (14). Cumulatively, these findings suggest that ascarosides represent a nematode-specific molecular signature that is recognized and interpreted by nematode predators and hosts across multiple kingdoms.In this study, we collected ES products from the gut-resident, rodent-parasitic nematode Nippostrongylus brasiliensis. Previous studies showed that the administration of N. brasiliensis ES (NES) products fully inhibits the development of airway hyperresponsiveness (AHR) in the ovalbumin (OVA) murine model of asthma (15). Specifically, NES products substantially prevented lung eosinophilia, mucus production, and resistance to airflow. Notably, it was found that heat-treated or proteinase K–treated NES mimicked the full effect of untreated NES products in reducing lung eosinophilia and OVA-specific IgG in serum. Therefore, we hypothesized that the therapeutic effect of NES products may be due to the presence of specific small molecules that may in part be bound to secreted proteins, explaining the activity of heat- or proteinase K–treated NES. To test this hypothesis, we isolated the small molecule fraction of heat-treated NES (small molecule ES [smES]) products via filtration through a 3-kDa filter and found that smES products strongly suppresses OVA-induced allergic immune responses. Parallel chemical analyses of several other mammalian parasitic nematodes confirmed the presence of specific ascarosides in smES products of all tested species. Next, we tested synthetic samples of ascarosides and found that ascr#7, a compound produced by N. brasiliensis and other parasitic species, markedly inhibited the development of allergic airway inflammation, comparable to the full effect of smES products. Mechanistically, we found that ascr#7 administration attenuated IL-33 production from lung epithelial cells and suppressed the proliferation of memory-type IL-5–producing pathogenic T helper 2 (Th2) cells and type 2 innate lymphoid cells (ILC2s) in the lung, both key drivers for the pathology of asthma. We thus demonstrate that ascarosides have an immunomodulatory role that attenuates OVA-induced allergic inflammation in a murine model.     

Synthesis of meso-porous α-Ga2O3 from liquid Ga metal having significantly high photocatalytic activity for CO2 reduction with water

We have succeeded in synthesizing meso-porous α-Ga₂O₃ which shows significantly high photocatalytic activity for CO₂ reduction with water. The sample was synthesized by hydroxidation of liquid Ga metal in water to obtain GaOOH and Ga(OH)₃, followed by the calcination of the mixed hydroxides at 773 K for 1 hour which converted them to meso-porous α-Ga₂O₃. The nano-pores remained as the trace of the evaporation of water produced by the oxidation of the hydroxides during the calcination. The photocatalytic activity of the synthesized meso-porous α-Ga₂O₃ for CO₂ reduction with water was as high as or higher than previous studies using various types of Ga₂O₃ with and without cocatalysts.

Meso-porous α-Ga₂O₃ showing quite high photocatalytic activity for CO₂ reduction with water is successfully synthesized from liquid Ga metal.     

Epstein-Barr Virus-positive Intestinal Diffuse Large B-cell Lymphoma in a Japanese Patient with Celiac Disease: First Reported Case and a Literature Review

A 60-year-old Japanese woman was diagnosed with celiac disease (CeD) and treated with a gluten-free diet. For five years, she had a good clinical course. However, she complained of inappetence and nausea. Colonoscopy revealed ulcerative tumors in the terminal ileum. A histological examination of biopsy specimens from the ulcerative tumor showed diffuse infiltration of large atypical lymphocytes. Immunohistologically, the atypical lymphoid cells were positive for cluster of differentiation (CD)10 and CD20. Many Epstein-Barr virus-encoded small RNA (EBER)-positive atypical lymphocytes were detected by in situ hybridization. This represents the first reported case of Epstein-Barr virus-positive intestinal diffuse large B-cell lymphoma complicated with CeD.