Lubiprostone Increases Small Intestinal Smooth Muscle Contractions Through a Prostaglandin E Receptor 1 (EP1)-mediated Pathway

Background/Aims Lubiprostone, a chloride channel type 2 (ClC-2) activator, was thought to treat constipation by enhancing intestinal secretion. It has been associated with increased intestinal transit and delayed gastric emptying. Structurally similar to prostones with up to 54% prostaglandin E2 activity on prostaglandin E receptor 1 (EP1), lubiprostone may also exert EP1-mediated procontractile effect on intestinal smooth muscles. We investigated lubiprostone's effects on intestinal smooth muscle contractions and pyloric sphincter tone. Methods: Isolated murine small intestinal (longitudinal and circular) and pyloric tissues were mounted in organ baths with modified Krebs solution for isometric recording. Basal muscle tension and response to electrical field stimulation (EFS; 2 ms pulses/10 V/6 Hz/30 sec train) were measured with lubiprostone (10-10-10-5 M) ± EP1 antagonist. Significance was established using Student t test and P < 0.05. Results: Lubiprostone had no effect on the basal tension or EFS-induced contractions of longitudinal muscles. With circular muscles, lubiprostone caused a dose-dependent increase in EFS-induced contractions (2.11 ± 0.88 to 4.43 ± 1.38 N/g, P = 0.020) that was inhibited by pretreatment with EP1 antagonist (1.69 ± 0.70 vs. 4.43 ± 1.38 N/g, P = 0.030). Lubiprostone had no effect on circular muscle basal tension, but it induced a dose-dependent increase in pyloric basal tone (1.07 ± 0.01 to 1.97 ± 0.86 fold increase, P < 0.05) that was inhibited by EP1 antagonist. Conclusions: In mice, lubiprostone caused a dose-dependent and EP1-mediated increase in contractility of circular but not longitudinal small intestinal smooth muscles, and in basal tone of the pylorus. These findings suggest another mechanism for lubiprostone's observed clinical effects on gastrointestinal motility

Stretta Radiofrequency Treatment for GERD: A Safe and Effective Modality

Gastroesophageal reflux disease is one of the leading gastrointestinal disorders. Current treatments include lifestyle modifications, pharmacological therapies, surgical fundoplications, and, more recently, endoscopic procedures. The rising concern of long-term side effects of the popular proton-pump inhibitors and the more recent evidence raising doubts about the durability of fundoplication have spurred reinterest in endoscopic procedures to treat reflux disorders. In the aftermath of several innovative antireflux procedures that were introduced and failed clinically or financially over the past decade, there is lingering confusion regarding the merits of the presently available interventions. This paper focuses on one endoscopic procedure, Stretta, which now enjoys the longest experience, a recent meta-analysis, and robust data supporting its safety, efficacy, and durability. Stretta reduces esophageal acid exposure, decreases the frequency of transient lower esophageal relaxation, increases patient satisfaction, decreases medication use, and improves quality of life. As such, this procedure remains a valuable nonsurgical treatment option in the management of gastroesophageal reflux disease

Endoscopic Optical Coherence Tomography for Clinical Gastroenterology

Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems. Keywords: optical coherence tomography; optical biopsy; endoscopic imaging; Barrett’s esophagus; inflammatory bowel diseaseNational Institutes of Health (U.S.) (Grant R01-CA75289-17)National Institutes of Health (U.S.) (Grant R44-CA101067-06)National Institutes of Health (U.S.) (Grant R01-CA178636-01)National Institutes of Health (U.S.) (Grant R44EY022864-01)National Institutes of Health (U.S.) (Grant R01-EY011289-27)National Institutes of Health (U.S.) (Grant R01-NS057476-05)United States. Air Force Office of Scientific Research (Grant FA9550-12-1-0499)United States. Air Force Office of Scientific Research (Grant FA9550-10-1-0551

Generation of Knockout Rats with X-Linked Severe Combined Immunodeficiency (X-SCID) Using Zinc-Finger Nucleases

Background: Although the rat is extensively used as a laboratory model, the inability to utilize germ line-competent rat embryonic stem (ES) cells has been a major drawback for studies that aim to elucidate gene functions. Recently, zinc-finger nucleases (ZFNs) were successfully used to create genome-specific double-stranded breaks and thereby induce targeted gene mutations in a wide variety of organisms including plants, drosophila, zebrafish, etc. Methodology/Principal Findings: We report here on ZFN-induced gene targeting of the rat interleukin 2 receptor gamma (Il2rg) locus, where orthologous human and mouse mutations cause X-linked severe combined immune deficiency (X-SCID). Co-injection of mRNAs encoding custom-designed ZFNs into the pronucleus of fertilized oocytes yielded genetically modified offspring at rates greater than 20%, which possessed a wide variety of deletion/insertion mutations. ZFN-modified founders faithfully transmitted their genetic changes to the next generation along with the severe combined immune deficiency phenotype. Conclusions and Significance: The efficient and rapid generation of gene knockout rats shows that using ZFN technology is a new strategy for creating gene-targeted rat models of human diseases. In addition, the X-SCID rats that were established in this study will be valuable in vivo tools for evaluating drug treatment or gene therapy as well as model systems for examining the treatment of xenotransplanted malignancies

The arousal level of consciousness required for working memory performance: An anaesthesia study

Osaka M., Minamoto T., Ikeda T., et al. The arousal level of consciousness required for working memory performance: An anaesthesia study. European Journal of Neuroscience 59, 3151 (2024); https://doi.org/10.1111/ejn.16383.Regarding the stage of arousal level required for working memory to function properly, limited studies have been conducted on changes in working memory performance when the arousal level of consciousness decreases. This study aimed to experimentally clarify the stages of consciousness necessary for optimal working memory function. In this experiment, the sedation levels were changed step-by-step using anaesthesia, and the performance accuracy during the execution of working memory was assessed using a dual-task paradigm. Participants were required to categorize and remember words in a specific target category. Categorization performance was measured across four different sedative phases: before anaesthesia (baseline), and deep, moderate and light stages of sedation. Short-delay recognition tasks were performed under these four sedative stages, followed by long-delay recognition tasks after participants recovered from sedation. The results of the short-delay recognition task showed that the performance was lowest at the deep stage. The performance of the moderate stage was lower than the baseline. In the long-delay recognition task, the performance under moderate sedation was lower than that under baseline and light sedation. In addition, the performance under light sedation was lower than that under baseline. These results suggest that task performance becomes difficult under half sedation and that transferring information to long-term memory is difficult even under one-quarter sedation

Markers of Memory CD8

BNT162b2, a nucleoside-modified mRNA vaccine for SARS-CoV-2 spike glycoprotein (S), provides approximately 95% efficacy for preventing COVID-19. However, it remains unclear how effectively memory CD8+ T cells are generated and which genetic and environmental factors affect the generation and function of memory CD8+ T cells elicited by this vaccine. Here, we investigated the frequency and functions of memory CD8+ T cells 3 weeks after the second vaccination in the Japanese population. Using a peptide-MHC pentamer, we detected an increased number of memory CD8+ T cells together with increased serum anti-S protein antibody in females compared with that in males, but the frequency of pentamer-positive cells was not positively correlated with antibody titers. Memory precursor effector cells (KLRG1-CD127+) among both CD8+ cells and pentamer+ cells and effector cells (CD38-HLA-DR+) among pentamer+ cells were more abundant in females than in males. Upon S protein-mediated stimulation of T cells, the intensity of CD107a and granzyme B expression was increased in females compared with that in males, indicating stronger memory CD8+ T cell responses in females than in males. Our studies showed that the BNT162b2 vaccine elicits increased memory CD8+ T cell proliferation and secondary CTL responses in females compared with those in males in the Japanese population. These findings provide an important basis for the distinct sex difference in cellular immune responses to mRNA vaccination and suggest that memory precursor effector cells can be one of markers to evaluate and boost cellular immunity induced by BNT162b2

Three-dimensional endoscopic optical coherence tomography imaging of cervical inlet patch

A 30-year-old white man with established Barrett’s esophagus (BE) and continued symptoms of chronic severe heartburn, persistent cough, throat irritation, and asthma was referred for surveillance EGD at the VA Boston Healthcare System. During retraction of the endoscope, a pink circular lesion (A) was observed under white light endoscopy in the upper esophagus (spanning 20–22 cm from the incisors). Three-dimensional endoscopic optical coherence tomography (OCT) images were obtained of the region under direct visualization with white light by passing the probe through the standard accessory channel. An en face projection image (B) at 400-μm depth underneath the tissue surface showed columnar epithelium consistent with a cervical inlet patch (CIP) and surrounding normal squamous epithelium (SE). Cross-sectional OCT images along the probe pull-back direction (C) and the probe rotation direction (D and F) clearly demonstrated columnar and squamous epithelium in the CIP region and the surrounding esophagus, respectively. Biopsy specimens taken from the imaged lesion confirmed the finding of CIP. The OCT features matched representative hematoxylin and eosin histology (E and G). Both esophageal and extraesophageal symptoms responded to increased antacid therapy.United States. Veterans AdministrationNational Institutes of Health (U.S.) (Grant R01-CA75289-14)United States. Air Force Office of Scientific Research (Contract FA9550-10-1-0063)United States. Dept. of Defense. Medical Free Electron Laser Program (Contract FA9550-10-1-0551)MIT/Center for Integration of Medicine and Innovative Technology (Medical Engineering Fellowship)National Science Council of Taiwan (Taiwan Merit Scholarship

Single-molecular real-time deep sequencing reveals the dynamics of multi-drug resistant haplotypes and structural variations in the hepatitis C virus genome

While direct-acting antivirals (DAAs) for hepatitis C virus (HCV) have dramatically progressed, patients still suffer from treatment failures. For the radical eradication of HCV, a deeper understanding of multiple resistance-associated substitutions (RASs) at the single-clone level is essential. To understand HCV quasispecies and their dynamics during DAA treatment, we applied single-molecule real-time (SMRT) deep sequencing on sera from 12 patients with genotype-1b HCV infections with DAA treatment failures, both pre- and post-treatment. We identified >3.2 kbp sequences between NS3 and NS5A genes of 187, 539 clones in total, classifying into haplotype codes based on the linkage of seven RAS loci. The number of haplotype codes during the treatment, per sample, significantly decreased from 14.67 ± 9.12 to 6.58 ± 7.1, while the number of nonsynonymous codons on the seven RAS loci, per clone, significantly increased from 1.50 ± 0.92 to 3.64 ± 0.75. In five cases, the minority multi-drug resistant haplotypes at pre-treatment were identical to the major haplotypes at relapse. Moreover, various structural variations (SVs) were detected and their dynamics analysed. These results suggest that SMRT deep sequencing is useful for detecting minority haplotypes and SVs, and to evaluate the dynamics of viral genomes at the single-clone level

Moderate sedation induced by general anaesthetics disrupts audio-spatial feature binding with sustained P3 components in healthy humans

Minamoto Takehiro, Ikeda Takashi, Kang Hongling, et al. Moderate sedation induced by general anaesthetics disrupts audio-spatial feature binding with sustained P3 components in healthy humans. Neuroscience of Consciousness 2018, 876 (2018); https://doi.org/10.1093/nc/niy002.Feature binding is considered to be the basis for conscious stimulus perception, while anaesthetics exert a gradient effect on the loss of consciousness (LOC). By integrating these two streams of research, the present study assessed the effect of two anaesthetic agents (i.e. propofol and midazolam) on audio-spatial feature binding. We also recorded the electrophysiological activity of the frontal channels. Using pharmacokinetic simulation, we determined the effect-site concentration (Ce) of the anaesthetics at loss of response to verbal command and eyelash reflex. We subsequently adjusted Ce to 75%, 50% and 25% of Ce-LOC to achieve deep, moderate and light sedation, respectively. Behavioural results showed that moderate sedation selectively disrupted feature binding. The frontal channels showed a P3 component (350–600 ms peristimulus period) following the presentation of audio-spatial stimuli at baseline and under moderate and light sedations. Critically, the late event-related potential component (600–1000 ms) returned to the pre-activated level (0–350 ms) at baseline and under light sedation but was sustained under moderate sedation. We propose that audio-spatial feature binding may require the presence of a P3 component and its subsequent and sufficient decline, as under anaesthetic-induced moderate sedation the P3 component was sustained and featured binding was impaired