Effects of Several Denervation Procedures on Distribution of Calcitonin Gene-Related Peptide and Substance P Immunoreactive in Rat Stomach

The effect of chemical deafferentation, vagotomy(VGX), and gangliosympathectomy (GSX) on the density offibers containing calcitonin gene-related peptide (CGRP)and substance P (Sub.P) in the rat gastric wall was studied. Chemical deafferentation bycapsaicin abolished the density of CGRP-immunoreactive(IR) fibers, not Sub.P-IR fibers. Ten days after VGX,the density of CGRP-IR or Sub.P-IR fibers in the mucosa was largely reduced, while no reductionof CGRP-IR and Sub.P-IR fibers was seen in submucosaland muscular layers. GSX significantly reduced thedensity of CGRP-IR fibers in the mucosa and caused a moderate decrease in the fibers in submucosaland muscular layers. Pretreatment with6-hydroxydopamine, a neurotoxin for noradrenergicnerves, did not affect the density of CGRP-IR fibers inthe gastric wall. The density of Sub.P-IR fibers in thegastric wall was not affected by GSX. These studiesindicate that the CGRP-IR and Sub.P-IR fibers in themucosa are susceptible to extrinsic nerve denervation compared with those in the submucosa and musclelayers, that a major portion of the CGRP-IR fibers inthe mucosa is of both vagal and spinal origin, and thata major portion of the Sub.P-IR fibers in the mucosa is of vagal origin. Furthermore, thepresent results support that CGRP-IR fibers, notSub.P-IR fibers, in the rat stomach arecapsaicin-sensitive.     

Studies on the muscarine receptors in rat gastric smooth muscle

It has been reported that the two types of muscarinic receptors, "M1" and "M2", exist in the opossum lower esophageal sphincter. The presence of these muscarinic receptor subtypes had been confirmed with the discovery of the M1 selective antagonist, pirenzepine. But little is known about muscarinic receptor subtypes in gastric smooth muscle. The aim of this study was to identify the muscarinic receptor subtypes on the gastric smooth muscle responsible for the contraction of rat gastric muscle strip. Also, we examined the mechanism of the action of aclatonium napadisilate on rat gastric smooth muscle in vitro. The stimulation of M2 receptor caused the contraction of the gastric smooth muscle. McN-A-343, selective M1 agonist, caused weak contraction of the gastric smooth muscle, and this response was not affected by the selective M1 antagonist, pirenzepine. Aclatonium napadisilate stimulated M2 receptor and caused the gastric smooth muscle contraction. We conclude that the contraction of the gastric smooth muscle is caused by the stimulation of the M2 receptor and this reaction was not affected by tetrodotoxin, suggesting the M2 receptor is located directly on the gastric smooth muscle. The weak contraction of the gastric smooth muscle caused by McN-A-343 was not affected by the selective M1 antagonist, pirenzepine, suggesting that McN-A-343 may not be a pure M1 selective agonist. The action of aclatonium napadisilate is supposed to stimulate the M2 receptor.     

Changes of the beat amplitude power after partial left ventriculectomy and coronary artery bypass grafting

Partial left ventriculectomy (PLV) was originally introduced as a new surgical approach by patients with an end stage of cardiac disease. Coronary artery bypass grafting (CABG) is a standard procedures used in cardiac surgery. Multichannel ECG (MECG) measurements and body surface mapping (BSM) were used to analyse the normalised beat amplitude power maps (BAM) that reflect an overall cardiac activity. The resulting BAMs show that the amplitude of cardiac signals decrease for approximately 30% after the PLV and stay in the same level during the postoperative monitoring interval while after CABG no significant changes in BAM have been observed. In addition the electrodes from the body surface area above the left ventricle, where surgery was performed, show significant changes in beat amplitudes.     

Novel SARS-CoV-2 Variant in Travelers from Brazil to Japan

Multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with higher transmission potential have been emerging globally, including SARS-CoV-2 variants from the United Kingdom and South Africa. We report 4 travelers from Brazil to Japan in January 2021 infected with a novel SARS-CoV-2 variant with an additional set of mutations.     

Role of Laryngeal Movement and Effect of Aging on Swallowing Pressure in the Pharynx and Upper Esophageal Sphincter

Objectives Describe contribution of laryngeal movement to pressure changes at the upper esophageal sphincter (UES) and the effect of aging on the swallowing function. Study Design Manofluorography on 56 nondysphagic adults divided into three age groups: the 21‐ to 31‐year‐old group (n = 32), the 61‐ to 74‐year‐old group (n = 12) and the 75‐ to 89‐year‐old group (n = 12). Analyses of the bolus transit time, the amplitudes and durations of pharyngeal pressures, the timing of a pressure fall at the UES and the laryngeal movements. Methods Intraluminal strain‐gauge sensors recorded pressure changes in the oropharynx, hypopharynx and the UES. Motion pictures of the videotapes were fed into a personal computer, and movements of the hyoid bone were measured in both the horizontal and vertical directions as an indication of laryngeal movement. Results In 26‐ and 70‐year‐old men with calcification of the thyroid cartilage, it was determined that the larynx and hyoid bone moved in consonance until the end of the rapid hyoid movements in both the superior and anterior directions. In the 21‐ to 31‐year‐old group, the magnitude of the pressure fall at the UES was maximal before or almost at the same time as the bolus arrival, in preparation for smooth passage of the bolus from the pharynx to the esophagus. The rapid superior movements of the hyoid bone started significantly early as compared with its anterior movements (P = .0001). The rapid anterior movements of the hyoid bone started simultaneously with the pressure fall at the UES. In the elderly, all segmental transit times were significantly increased. The timing of the pressure fall at the UES was significantly delayed and the UES pressure reached its minimum value after arrival of the bolus at the UES. The minimum pressure at the UES increased to a significantly positive value. The rapid anterior movements of the hyoid were significantly delayed, suggesting that this delay causes the delay in the pressure fall at the UES. Conclusions The rapid superior and anterior movements of the hyoid bone are considered to start at the same time as those of the larynx. In the young group, it is suggested that superior laryngeal movement protects the lower airway prior to the anterior laryngeal movement, causing the pressure fall at the UES to enable the passage of a bolus into the UES. In the elderly, smooth passage of the bolus from the pharynx to the esophagus is hindered and the system that prevents aspiration is rendered inefficient by changes in the swallowing pressures and laryngeal movements with aging.